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Philippine Daylight Time UTC+9:00 as optional local time in the Philippines

https://www.timeanddate.com/time/change/philippines.html

110.54.241.54 (talk) 1:05, 9 March 2021 (UTC)

why does the division of the time zone in Ukraine perfectly coincide with the territories occupied by russia? 195.95.147.122 (talk) 13:50, 4 September 2023 (UTC)[reply]

commons:File:World Time Zones Map.png#Summary says: "Map of current de facto time zones." De facto means it shows the time zone used by those actually in control of the area. It doesn't judge who has the right to the area. PrimeHunter (talk) 21:35, 4 September 2023 (UTC)[reply]

So the map should note that it is "de facto" map. Right not it just misleads and creates an opionion of justification of the occupation. How man laymen will be searching what exactly the map says? I bet not a lot, but instead they will be appealing in their arguments to "Wiki says X territories are part of Y!". 194.44.99.8 (talk) 14:25, 16 November 2023 (UTC)[reply]

The international borders, shown with white lines on the map, are de jure. Only the separation between time zones, shown with red lines on the map, are de facto. The file description already says "de facto time zones". The map shows the occupied territories as part of Ukraine, not Russia, because the white line is the internationally recognized border. The red line is only the separation between time zones, just like other countries that have more than one time zone. The separation between time zones does not imply that the territories are part of Russia, it only means that the time observed in that area is UTC+3. Heitordp (talk) 17:05, 16 November 2023 (UTC)[reply]

In the article it says that poland is in gmt +1 timezone while it is gmt +2 78.11.151.141 (talk) 14:45, 26 October 2023 (UTC)[reply]

In the table in the article, Poland is listed in the row of UTC+1 but in the column of locations that use DST. See the note above the table in the article: "In the table below, the locations that use daylight saving time (DST) are listed in their UTC offset when DST is not in effect. When DST is in effect, approximately during spring and summer, their UTC offset is increased by one hour." Poland is in UTC+1 when DST is not in effect, but in UTC+2 when DST is in effect. Currently DST is in effect in Europe, but it will end this Sunday. Heitordp (talk) 16:16, 26 October 2023 (UTC)[reply]

I would like to see two maps, showing the effective time in December and June. That would show how the use of Daylight Shifting Time varies with latitude. —Tamfang (talk) 05:49, 20 December 2023 (UTC)[reply]

The article states that

A time zone is an area which observes a uniform standard time for legal, commercial and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time.

Time zones are defined as one or two offsets from Coordinated Universal Time (UTC), and (if two offsets are used) the days when the offset changes. Some time zones switch between offsets throughout the year due to daylight saving time (DST).

This seems to correspond to the notion of time zones as possibly being per-polity, so that, for example, the US states of Arizona and New Mexico are not in the same time zone, as (most of) Arizona does not observe DST, but New Mexico does.

However, the map at the top of the article, which is captioned "Time zones of the world", shows time zones defined only by the standard-time offset from UTC, so that Arizona and New Mexico are in the same time zone, the North American Mountain Time Zone.

The notion of time zone used in the tz database is closer to the first one, although that notion has to handle more than just standard and daylight saving time. For example:

• the rule that specifies when the offset changes can themselves change over time, and have changed in a lot of places, although, if "the days when the offset changes" refers to a set of rules for determining, for any given year, the days when the offset changes, that's handled by the definition above;
• Morocco adjusts its clocks for Ramadan;
• some entries in the tz database include the region the entry covers moving from one standard-time UTC offset from another.

See, for example, the map at the top of the tz database article, which is more complicated than the map at the top of time zone.

Some tz database documentation uses the term "timezone", with no space between "time" and "zone", to refer to the regions that a tz database entry covers, in a somewhat-subtle attempt to distinguish tz database entries from "time zones" in the sense in which "time zone" is used in the caption for the map. Guy Harris (talk) 22:24, 8 March 2024 (UTC)[reply]

@Guy Harris: I propose replacing the map with this SVG version that I recently made. It uses stripes for areas that observe two offsets, so it's closer to the definition in the article. In addition, this version uses intermediate colors instead of stripes for fractional hour offsets, which I think is clearer; lists the dates of offset changes below the map; uses less memory than the PNG version, without losing resolution; and can be edited more properly.

I think that the definition in the article already includes the case of Morocco. For clarity, I suggest changing the last sentence to: Some time zones switch between offsets throughout the year, usually due to daylight saving time (DST).

The tz database groups areas in the same time zone only if they have always shared the same time since 1970. But the map only considers what they currently observe. Heitordp (talk) 13:58, 10 March 2024 (UTC)[reply]

The proposed map applies to the "a zone represents a standard time offset from UTC" definition of "time zone", with stripes to indicate the portions of the zone where DST is observed"; it doesn't show differences between either current or past rules.

The article says

Time zones are defined as one or two offsets from Coordinated Universal Time (UTC), and (if two offsets are used) the days when the offset changes. Some time zones switch between offsets throughout the year due to daylight saving time (DST).

which covers Morocco in that it has two offsets; the second sentence doesn't say that the two offsets are necessarily due to DST, so that also can include the two offsets being due to Ramadan. Guy Harris (talk) 23:26, 10 March 2024 (UTC)[reply]