The scheduling of television programming in North America (namely the United States, Canada, and Mexico) must cope with different time zones. The United States (excluding territories) has six time zones (Hawaii–Aleutian, Alaska, Pacific, Mountain, Central and Eastern), with further variation in the observance of daylight saving time. Canada also has about six time zones (Pacific, Mountain, Central, Eastern, Atlantic and Newfoundland). Mexico has four time zones (Pacific, Mountain, Central, and Eastern). This requires broadcast and pay television networks in each country to shift programs in time to show them in different regions.
Canadian broadcasting networks, with six time zones and a much larger percentage of its audience residing in the Mountain Time Zone than in the Central Time Zone, are sometimes able to avoid the issues that affect American programming by airing pre-recorded programs on local time. CBC Television and CTV created delay centres in Calgary in the early 1960s in order to allow programming to air in each time zone based on the region.
In order to protect local advertising revenue, the "simsub" rules allow broadcast stations to require feeds of U.S. broadcast stations on local pay television to be "substituted" with the Canadian station's signal if they are airing the same program. This can affect how commercial broadcasters schedule their programming outside of Eastern and Pacific Time: in Alberta, U.S. stations from Spokane, Washington—a city in Pacific Time—have historically been carried on cable. As such, the Calgary/Edmonton stations of the major commercial networks may air certain programs an hour later in comparison to other markets, in order to maximize simsub opportunities with feeds originating from Pacific Time. Saskatchewan does not observe Daylight Saving Time, and matches Mountain Time when DST is in effect. However, local stations maintain the scheduling patterns of their affiliates in Manitoba (which are in Central Time, but do observe DST), and do not follow the schedule patterns of their Alberta counterparts when DST is in effect.
Unlike in the United States, virtually all live events, including live entertainment shows and sports television, are simultaneously broadcast nationwide in Canada. For instance, live shows in Canada are aired to entirety at the same time in all time zones based on Eastern time. Several live U.S. shows are also aired simultaneously in all of Canada, including for viewers in the Pacific Coast (unlike in the United States where some viewers on the same side of the continent depend on tape-delayed broadcasts for some otherwise live events). Conversely, live shows aired in Canada are frequently televised simultaneously for some viewers in the U.S. with access to Canadian broadcast networks.
The vast majority of specialty cable and satellite television channels in Canada each operate a single feed which is distributed in all time zones. This includes all French language channels, as they predominantly serve Francophone areas of the country, mostly in Quebec (almost all of which observes Eastern Time). Even many long-standing specialty channels with a general entertainment format use a single national feed, though in many cases they will repeat core primetime programming three hours after first broadcast, such that programs can be promoted as airing at the same time in both the Eastern and Pacific time zones.
Some specialty channels do operate two separate broadcast feeds for Eastern and Western Canada. The Eastern feed airs programs on an Eastern Time schedule, while the Western feed airs the same programming on a three-hour delay. The separation between feeds is typically implemented at the border between Manitoba and Ontario, which may result in a program that airs at 10:00 p.m. Eastern Time in Ontario not airing in Manitoba until midnight CT (whereas an equivalent program in the U.S. would typically be available at 9:00 p.m. for Central Time viewers). However, one channel, the Aboriginal Peoples Television Network, implements the separation at the border between Manitoba and Saskatchewan.
The Canadian Broadcast Standards Council (CBSC) applies more restrictive censorship regulations to broadcast programming shown in prime time, compared to content transmitted after a watershed hour beyond which few children would be likely to be watching. This can be problematic if the same content is broadcast simultaneously nationwide, as the 9:00 p.m. watershed in Vancouver falls at midnight in Toronto and 1:30 a.m. in St. John's. LGBT specialty broadcaster PrideVision was particularly affected as, from its launch in 2001 until 2005, its format included more innocuous entertainment programming aimed at the gay community during the day and in prime time and hardcore pornographic content in the overnight (with the latter expanding into the mid-evening by 2004). The network's adult programming was spun out into a second channel so that the parent network, now OutTV, could broadcast its non-explicit entertainment and lifestyle programming across its entire broadcast day.
With four time zones in the contiguous United States, American broadcast television networks generally broadcast at least two separate feeds to their owned-and-operated stations and affiliates, as do cable/satellite channels: the "eastern feed" that is aired simultaneously in the Eastern and Central Time Zones, and the "western feed" that is tape-delayed three hours for those in the Pacific Time Zone. This ensures that a program, for example, that airs at 8:00 p.m. ET on the East Coast is also shown locally at 8:00 p.m. PT on the West Coast. Networks may also broadcast a third feed specifically for the Mountain Time Zone, on which programs are usually broadcast on a one-hour delay from the Eastern Time Zone. Otherwise, some stations in the Mountain Time Zone use the western feed, while others get a mix of both the Eastern and Pacific feeds.
The Eastern Time Zone is commonly used as a de facto premier time for the United States as the region covered by the zone covers nearly half of the U.S. population and has the highest metropolitan area density within the country. Network promotions typically advertise airtimes either on Eastern Time only or, more commonly, in conjunction with airtimes in the Central and/or Pacific Time Zones.
Network stations in the Alaska and Hawaii–Aleutian Time Zones that draw from the "western feed" utilize the "local delay" scheduling approach applied to affiliate stations in the Central and Mountain zone that receive their network's "eastern feed." Daytime and prime time programming is transmitted simultaneously on network affiliates in the Pacific and Alaska Time Zones; stations in the Hawaii–Aleutian Time Zone transmit a secondary local feed, on which programs are usually broadcast on a two-hour delay from the Pacific Time Zone.
Effectively, the East, Mountain and West network feeds allow prime time on broadcast television networks to end at 10:00 p.m. Central, Mountain, Alaska and Hawaii–Aleutian, and 11:00 p.m. Eastern and Pacific. When it first expanded its programming into prime time in April 1987, Fox became the first major broadcast network in the U.S. to offer a "common prime" schedule; this type of scheduling subtracts an hour from the prime time schedule, reducing it to two hours on Monday through Saturdays and three hours on Sundays – ending evening network programming earlier than NBC, CBS and ABC did – and continue to do (Fox did expand its Sunday primetime schedule into the 10:00 p.m. timeslot in September 1987, before giving back that hour to its stations in September 1993). The WB and UPN followed the "common prime" scheduling model when they both launched in January 1995; the replacements for those networks, The CW and the MyNetworkTV program service, similarly used that model upon their launches in September 2006.
In 2009, PBS began using Internet servers instead of separate feeds for time delaying of its programming to the network's member stations. The servers imitate a delayed program feed, broadcasting the program at the correct airtime as if it were being broadcast via satellite. This was done as PBS had upgraded its main program feed to high definition (or to widescreen digital at the very least) in December 2008, but satellite capacity allowed for only Eastern and Pacific time zone feeds, prompting the removal of the Central and Mountain time zone feeds and a shared feed for Alaska and Pacific time zones in February 2009, which created complaints from PBS stations.
Subscribers to cable or satellite television services may still only receive East Coast feeds for certain channels even if they reside on the West Coast. Providers in Alaska and Hawaii may transmit either the Pacific Time Zone feed or the East Coast feed, depending on the service and/or channel. Some cable channels only offer one broadcast feed, where viewers see the same program in all time zones. For example, until it dropped the program in 2014, superstation-turned-basic cable channel WGN America (now NewsNation) telecast the noon (Central Time) newscast from WGN-TV in Chicago at 1:00 p.m. Eastern in Washington, D.C. and 10:00 a.m. Pacific in Los Angeles.
Broadcasters offer East and West Coast feeds of some basic cable channels for viewing in all time zones. The usage of dual feeds of the same channel is a commonplace method for premium channels such as HBO, Cinemax, Showtime and Starz, in which the Pacific time zone feed of the primary channel is packaged with the East Coast feed of the main channel and the pay service's multiplex channels, if the premium channel has any. (Epix subverts this as its Eastern Time feed acts as the default main channel feed available to most contracted providers and its TV Everywhere and OTT streaming platforms, while its Pacific feed is mainly restricted to systems in the Western United States.) HBO maintains a separate Hawaii–Aleutian Time feed of its primary channel; the three-hour-delayed version of the Pacific Time feed—which is exclusively carried by the state's dominant cable provider, Oceanic Spectrum—is the only Hawaii-specific timeshift feed currently maintained by an American cable-originated network. (The state's other major cable provider, Hawaiian Telcom, transmits the Pacific Time feeds of all seven HBO channels, which Oceanic also packages with the main channel's Hawaii–Aleutian Time feed.)
Most commonly, the Eastern and Pacific Time Zone feeds of only the main channel are packaged together, although some providers may also provide both coastal feeds of a premium service's multiplex channels. In some cases, cable networks (such as cable news and sports channels) "fake" the dual feed approach by recycling their same-day prime time programming during the overnight hours on a three (or four) hour cycle; in this case, the programs are automatically rebroadcast at the advertised time (or one hour later) in the Pacific Time Zone.
In the United States, distant over-the-air broadcast stations affiliated with the six broadcast networks are offered by direct-broadcast satellite providers as well as C-band services that do not offer locally based affiliates for most individual markets, allowing viewers to choose between the east and west feeds of a given network. These designated stations are usually owned-and-operated stations and/or affiliates of ABC, NBC, CBS, Fox and The CW located in the Eastern and Pacific Time Zones (usually those based in New York City and Los Angeles such as ABC's respective O&Os [network owned-and-operated] in those markets, WABC-TV and KABC-TV). Dish Network and C-band providers also provide CW and MyNetworkTV affiliates designated as superstations (such as WPIX in New York and KTLA in Los Angeles), with Dish mainly making them available in markets where it does not carry a low-power, digital subchannel-only or non-broadcast affiliate of either network (especially in markets served by The CW's quasi-national feed for areas ranked below #98 in Nielsen Media Research market rankings, The CW Plus).
The country's two major satellite providers – DirecTV and Dish Network – only offer these de facto coastal feeds in order to provide programming from at least one network to subscribers living in smaller media markets or rural areas where a network does not have a local affiliate available on the provider, if even presently serving the given location at all. Since the services began offering local network affiliates from additional markets in the early 2000s, many local stations have successfully sued DBS providers to deny access to distant stations carrying programming from the same network as them within their markets. This differs from the subscription television model in Canada, most cable and satellite providers carry distant over-the-air broadcast stations from the U.S. (consisting of both affiliates of the Big Four broadcast networks and minor network affiliates classified as superstations), in addition to O&Os and affiliates of domestically-based networks.
Most sports television programs, including other major national events, are broadcast live in all time zones across U.S. territories, but also present special problems for local stations. For such events, the networks may either advertise Eastern time only, or list the times in both Eastern and Pacific (e.g. "8 p.m. Eastern/5 p.m. Pacific"). As such, a live Sunday sporting event that is played from 1:00 to 4:00 p.m. Pacific Time preempts local 6:00 p.m. newscasts on the East Coast. Likewise, a State of the Union address that is televised at 9:00 p.m. Eastern Time preempts local 6:00 p.m. newscasts on the West Coast. Similarly, as sports programs would normally air weekend afternoons on the east coast on major TV networks and late mornings on the west, the weekend editions of national morning news shows could air on the west as early as 5:00 or 6:00 a.m. PT. News channels such as CNN and sports channels such as ESPN that frequently broadcast live events offer a single feed that airs in all time zones. About 80% of the U.S. population reside in the Central and Eastern time zones, where the nation's largest city (and the main anchor of television programming) New York is located.
A notable exception to live telecasts in sports is the Olympic Games. Although it has provided live coverage of events during other dayparts via platforms such as cable and streaming, NBC's flagship primetime coverage block has typically featured tape-delayed and "plausibly live" presentations of events from earlier in the day. When allowed by the host's time zone, NBC does include live coverage of selected events in the block. This practice is reflected in the actual scheduling of the Olympic program, which NBC may influence to maximize primetime viewership due to the value of its broadcast rights: at the 2008 Summer Olympics in Beijing, many swimming events were held in the morning local time to allow for primetime broadcasts in the Americas). This coverage block was, in turn, aired in tape delay on the West Coast. This occurred even during the 2010 Winter Olympics, which were held in the Pacific Time city of Vancouver.
Beginning with the 2018 Winter Olympics in Pyeongchang, except for the ceremonies (which are tape-delayed and aired at the same time across all time zones), NBC adopted a new format for its primetime Olympics coverage, allowing for the first predominantly live nationwide U.S. television coverage of the Olympic Games. NBC cited the "communal" experience, increased use of social media, and criticism of the prior format for this transition. Eventually, most figure skating events were scheduled for this window. Despite the U.S. absence in the 2018 FIFA World Cup, Fox followed suit by televising all of its matches live in all U.S. territories simultaneously, resolving the longstanding complaints by viewers on its former broadcast delay of the said event. This marked the first time in U.S. television history that the world's three biggest sporting events – the FIFA World Cup, the Olympic Games and the Super Bowl – have been aired live nationwide (and simultaneous with the live global transmissions) in the same year.
Until recently, several entertainment shows that are broadcast live in the Eastern and Central time zones, including some that originate from Los Angeles (particularly live reality competition shows as ABC's Dancing with the Stars and NBC's The Voice), were tape-delayed in the Mountain and Pacific time zones, thus making it impossible for viewers in those time zones to vote after performance episodes of live reality competition shows finish airing live on the East Coast. Other special annual entertainment events like the Miss America and Miss USA pageants have continuously aired on a broadcast delay for U.S. West Coast, wherein the same protocol is still being applied by the Miss Universe (headquartered in the U.S.) and Miss World pageants despite their yearly live global simultaneous telecasts.
The mechanics of the 2014 ABC series Rising Star — which allowed for live, real-time voting by viewers – would allow the insertion of live reaction segments in the event that a contestant eliminated by low vote totals in the original Eastern/Central/Mountain time zone broadcast would be saved by results watching the Pacific/Alaska broadcast, but the show was broadcast live across the mainland U.S. except the Pacific time zone. Alaskan viewers were able to participate in the voting process due to having to be one hour behind of Pacific Time and having to be following schedules similar to that of Central and Mountain Time, while Hawaii and American Samoa are left out of the show's real-time voting process due to multiple-hour time differences. Moreover, ABC noted that the chances of West Coast votes differing substantially from other viewers was statistically small.
The Academy Awards, up until the early 21st century, were the only major U.S. entertainment television event to have been aired live to all continental U.S. time zones. Hawaii and American Samoa also began receiving simultaneous live broadcasts in 2016, although delayed telecasts were used in 2017 and 2018. In 2009, however, the Golden Globe Awards ushered the era of U.S. awards shows transitioning to live coast-to-coast telecasts in response to longstanding general criticisms of some live shows being televised real-time to the East Coast but tape-delayed for West Coast viewers, even when those shows originated from Los Angeles area. Viewers in the Pacific, Mountain, and Alaskan time zones had frequently complained about spoilers made by live viewers east of the Rockies during the broadcasts.
The Grammy Awards historically delayed its live ceremonies for West Coast viewers. In 2016, however, CBS began to allow its stations in the Western U.S. to carry the ceremony live as long as they also carried a prime time rebroadcast, before mandating all of its affiliates to air Grammys live all across the U.S. (inclusive of time zones outside the contiguous U.S.), with corresponding primetime rebroadcasts for viewers outside the Eastern and Central time zones. Despite shifting venues between Los Angeles and New York since 2018, the Grammys have continued to use the format, making it the first major award show to have consistently aired live every year across all U.S. time zones. Although the Primetime Emmy Awards, currently aired in rotation by ABC, CBS, Fox and NBC, began airing live coast-to-coast in the U.S. in 2010, the awards show followed suit with the Grammys in airing live simultaneously outside the contiguous U.S. time zones with CBS' telecast in 2017.
The Tony Awards (which are usually broadcast live from New York City) remain the only major award show to have never conducted live nationwide telecasts in the U.S. Some special music telecasts originating from Los Angeles, such as the American Music Awards, People's Choice Awards and Teen Choice Awards, continue to air live in the U.S. East Coast and tape-delayed elsewhere, as their airtime is often purchased as a brokered programming arrangement, which also allows standards and practices to watch the ceremony in advance and determine cuts for profanity or content to insert a bleep censor or cut-away, as well as cuts for time and superfluous items such as longer walks than expected by an award winner to the stage or a rare botched performance with the replacement of dress rehearsal footage. The Billboard Music Awards have since juggled between tape-delayed West Coast airings and live coast-to-coast U.S. telecasts since the mid-2010s, while the MTV Video Music Awards were previously edited before being recorded for broadcast on separate local primetime slots for both coasts, before switching back to live telecasts in all U.S. territories by the late 2010s.
New Year's Eve specials covering Times Square's ball drop in New York City are typically broadcast live in the Eastern and Central time zones and tape-delayed elsewhere in the country so that the countdown will correspond with the local time zone. Some affiliates may preempt the late-night segment of the networked special in order to broadcast local celebrations (such as Seattle's KING-TV, which preempts the already tape-delayed NBC's New Year's Eve to broadcast coverage of midnight fireworks on the Space Needle), and it is not uncommon for stations in Central Time to air a local New Year's special immediately after the conclusion of the network special, especially if it does not produce additional coverage focused on the area (such as ABC's New Year's Rockin' Eve, which since 2017 has featured segments and coverage of midnight celebrations in New Orleans, and Late Night with Conan O'Brien, which did so to lampoon the bias towards New York in New Year's coverage). NBC's coverage of Macy's Thanksgiving Day Parade in New York City is shown live only in the U.S. Eastern time zone as well as Puetro Rico and the US Virgin Islands due to the affiliates in these territories using the Eastern Time Zone feed although starting at 10:00 a.m. AST; west of there, the broadcast starts at 9:00 a.m. local time in each time zone. Guam on the other hand, being ahead with the rest of the United States, airs the event the next day after Thanksgiving but at the same time as all other times zones except for Eastern Time.
Occasionally, networks will produce and broadcast the same live event twice in one night – broadcasting once on an East Coast feed, and again on a West Coast feed three hours later. This permits more viewers to watch the broadcast live in prime time (although not all), as the show can air in its usual timeslot in all markets, but incurs the expense and difficulty of delivering two live broadcasts. In some cases, the two broadcasts may intentionally differ, prompting fans to compare notes and post scenes from each version online. While rare, the technique of multiple live broadcasts has been not uncommon for some special live episodes of scripted programs since the late 1990s, such as the 30 Rock episodes "Live Show" and "Live from Studio 6H", Will & Grace with "Alive and Schticking", The West Wing with "The Debate", and ER's fourth-season debut with "Ambush".
Few regularly scheduled prime time shows, both scripted and non-scripted, and sports and non-sports in genre, have been aired to totality at the same time live across all continental U.S. time zones. This format, similar to aforementioned major awards shows, involves airing live on prime time or late night in the East Coast (and late afternoon hours or on prime time, simultaneously and respectively, on the West Coast). NBC remains the foremost proponent of live television, with its broadcasts of Sunday Night Football and Saturday Night Live being transmitted live across the contiguous U.S. states (and for the former, including for U.S. time zones outside the mainland), with a corresponding prime time or late-night encore for viewers outside the Eastern and Central time zones.
In mid-2018, American Idol became the first ever reality competition series – and first ever non-weekend regularly scheduled prime time program – in all of U.S. television to broadcast live in all U.S. territories upon its revival on ABC after its initial first-run finale on Fox in 2016, beginning with its live shows in the final stages of the competition. In this manner, viewers in all U.S. territories are enabled to both view the episodes live at the same time, with the prime time East Coast telecast coinciding with the real-time afternoon telecasts across the Pacific to Hawaii, along with real-time voting with the revealing of its results integrated at the end of the performance nights. Despite the format having been in place for the show since 2015, as part of its nationwide voting expansion, a corresponding warning for viewers outside the Eastern and Central time zones regarding the closing of the voting window will be aired upon their local prime time encore broadcasts. The format would eventually extend to include the season finale round beginning 2019, making it the first ever primetime regular series in U.S. television history to air its season finale live all across the U.S.
In 2020, however, the ongoing COVID-19 pandemic caused the worst disruption in the annual U.S. network television schedule since the 2007-08 Writers Guild of America strike, severely curtailing several live show productions. The 2020 editions of the Academy Awards and the Super Bowl (by the National Football League) became the last major annual television events to have been broadcast live globally from the U.S. prior to the occurrence of the pandemic. Numerous non-scripted programs with live season finales, such as Saturday Night Live, American Idol, The Voice and Survivor, had seen their season-long runs drastically shortened for the year to accommodate for remote productions outside the major network studios, which also featured a temporary return to delayed telecasts outside the U.S. Central and Eastern time zones. NBC was also forced to readjust its broadcast rights to the Olympic Games after the Tokyo Olympics was postponed to 2021 as a result of the disruption in the annual sports calendar due to the pandemic. Later that same year, the MTV Video Music Awards became the first awards show to air live in all U.S. territories since the beginning of the pandemic.
Local stations and affiliates must schedule their local and syndicated programming around their respective network's feed. Because primetime programs on the East Coast feed are simulcast in two time zones, stations in the Central Time Zone are affected differently from those in the Eastern Time Zone. An hour of syndicated programming time (between 7:00 and 8:00 p.m. in the Eastern and Pacific time zones) is lost in the Central and Mountain time zones since network primetime in those areas starts at 7:00 p.m., forcing stations in Mountain or Central time (or in parts of both zones) to choose between airing their 6:00 p.m. newscast and another syndicated or locally produced program or airing shows in "blocks" preferred by syndicators (for example, Wheel of Fortune and Jeopardy! together or Entertainment Tonight and The Insider together).
The most common set of programming chosen by stations aligned with the Big Three television networks (ABC, CBS and NBC) is to air a local newscast at 5:00 p.m., national news at 5:30 p.m., another local newscast at 6:00 p.m. and syndicated programming at 6:30 p.m., though some Fox stations that maintain a newscast schedule comparable to stations tied to the Big Three (commonly stations that were former ABC, NBC and CBS affiliates themselves) carry a 60- or 90-minute block of news from 5:00 to 6:00 (or 6:30) p.m. with an additional half-hour of local news in the 5:30 p.m. timeslot as Fox does not air a national evening newscast; a few stations not affiliated with the Big Four networks, such as WGN-TV, KTLA in Los Angeles and WJXT in Jacksonville, Florida, follow a similar scheduling format with their early evening newscasts. Most Big Three affiliates in the Eastern and Pacific time zones follow this early evening newscast model as well, running a 90-minute block of news from 5:00 to 6:30 p.m., particularly if they run a network's national evening newscast at 6:30 p.m. Eastern and Pacific Time. Some stations, regardless of time zone, even show a newscast from 6:00 to 7:00 p.m., which if run on a network station in the Central or Mountain time zones would lead into primetime network programming. Some television stations (such as WKYC and WJW in Cleveland, Ohio, or WJAR in Providence, Rhode Island) have recently begun using the fact that primetime in the Eastern Time Zone begins at 8:00 p.m. to their advantage by carrying a newscast during the 7:00 p.m. hour, generally in order to attract viewers who work longer days and cannot return home to watch a 5:00 or 6:00 p.m. newscast.
Many stations that do not carry a newscast in the 6:00 p.m. timeslot in the Central Time Zone (commonly independent stations and most affiliates of non-historical networks like Fox – which has some stations that air a 6:00 p.m. newscast, though this is not entirely commonplace – The CW and MyNetworkTV) air situation comedies or other types of syndicated programming, such as reality series or game shows, during that hour. Many stations in the Central Time Zone tend to air one or both parts of the syndicated block at 5:00 p.m. or even earlier. Another more recent dilemma of the 7:00 p.m. primetime start is that a combination of longer commutes and work hours than in the past have caused many people to not come home from work until after 7:00 p.m., cutting into the potential ratings of shows that start at this time. Of course, the reverse is also true since simultaneous broadcasts offer viewers the chance to watch "prime time television" without having to stay awake until 11:00 p.m.
Local programming such as locally produced newscasts are not typically affected as many stations air their morning newscast at 4:00, 4:30, 5:00 or 5:30 a.m., and their early evening newscasts at 5:00 and/or 6:00 p.m.; however, the late evening newscast is affected due to the differences in time between time zones, meaning that if the late local news starts at 10:00 p.m. Central time on one network station, an affiliate of the same network in the Eastern Time Zone airs its newscast at 11:00 p.m.; network evening newscasts on CBS, ABC, and NBC are affected since they are usually scheduled to air at 6:30 p.m. Eastern Time (barring preemption due to network sports coverage or at the discretion of the local station, breaking news or severe weather coverage) in order to sync up with its simultaneous broadcast in the Central Time Zone. Midday newscasts are not necessarily affected, depending on whether the station's affiliated network schedules their daytime lineup simultaneously in the Eastern and Central Time Zones (as with ABC and CBS) or just to the Eastern Time Zone first (as with NBC). The late night program lineups on ABC, CBS, NBC and Fox are also similarly timeshifted, airing a half-hour later (after a newscast or syndicated programming if the station does not run news programming) but are shifted due to the time zone differences (a bigger issue with first-run late night programs that air after 12:30 a.m. Eastern Time since the later start time may subject these programs to a potentially decreased audience). Many Fox, CW and MyNetworkTV affiliates, and some independent stations carry a prime time newscast that is similarly affected by the timeshifting of the prime time schedule, meaning that if said late evening newscast starts at 9:00 p.m. Mountain Time on one network station, an affiliate of the same network in the Pacific time zone would air its news at 10:00 p.m.