Köppen climate types of New Jersey, using 1991-2020 climate normals.

The climate of New Jersey classification of the U.S. state of New Jersey is humid subtropical in South Jersey with a humid continental climate in North Jersey, particularly in the northwestern area of the state. The northwest part of New Jersey is the snowiest due to the higher elevations that earn it a Dfb classification. During the winters, New Jersey can experience Nor'easters, which are snowstorms that affect the Northeastern United States, and Atlantic Canada. However, many would-be snow events in the state end up turning to rain due to warm ocean air being brought in by the storm.[failed verification] [1] New Jersey's climate is shaped by its proximity to the Atlantic Ocean which provides moisture and moderates temperatures.[2] According to climatology research by the U.S. National Oceanic and Atmospheric Administration, New Jersey has been the fastest-warming state by average air temperature over a 100-year period beginning in the early 20th century,[3] related to global warming.

Temperatures

Average daily low temperature in January
Average daily high temperature in July

Temperatures are usually coolest in the northwestern part of the state and warmest in the southern part of the state. The temperature difference is greatest in the winter and the least in the summer. All parts of the state have recorded temperatures below 0 degrees and in excess of 100 degrees. The average number of freeze free days ranges from 163 days in the highlands to 217 along the coast.[4] The highest recorded temperature in the state of New Jersey was 110° on July 10, 1936 in Runyon and the lowest was -34°F in River Vale on January 5, 1904. [5] The hardiness zone ranges from 5b in high areas of Sussex County to 8a in parts of Atlantic City and Cape May.

Precipitation

The average annual precipitation in New Jersey ranges from 40 inches along the southeastern coast to around 51 inches in the north-central part of the state. The driest season is usually autumn which has an average of 8 days per month with measurable precipitation. During other seasons the average month has between 9 and 12 days of precipitation. Most areas receive between 25-30 thunderstorms a year. While tornadoes are possible, they tend to be rare and weak. There are usually about five tornadoes reported each year statewide.[4] The greatest 24-hour rainfall was 14.81 inches, which occurred in Tuckerton on August 19 - 20, 1939.[5]

Snowfall

Snow is relatively common in New Jersey, with most of it occurring between November 15 and April 15. Significant snowfall is much rarer along the coastline and in South Jersey than in Interior North Jersey. [4] The record for 24-hour snowfall is 32 inches in Rutherford on December 14, 1915. The greatest snow depth ever recorded was 52 inches at the Canistear Reservoir in Vernon Township on February 5, 1961.[5]

Climate change

Climate change is affecting New Jersey faster than much of the rest of the United States. New Jersey has warmed up faster than any other U.S. state by average air temperature over a 100-year period beginning in the early 20th century.[3] Not also to mention that New Jersey's rapid urban and suburban development over 20th century has contributed to "warming faster" than other states in past 100 years. This issue is called urban heat island effect. This is largely due to our small size and high urban to rural proportion than other state.[6]

Climate data for select cities

Climate data for Atlantic City, New Jersey (downtown), 1991–2020 normals,[a] extremes 1874–present[b]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 72
(22)
77
(25)
86
(30)
91
(33)
95
(35)
99
(37)
102
(39)
104
(40)
94
(34)
91
(33)
80
(27)
74
(23)
104
(40)
Mean maximum °F (°C) 63.5
(17.5)
64.8
(18.2)
73.2
(22.9)
83.2
(28.4)
89.3
(31.8)
94.5
(34.7)
96.9
(36.1)
94.6
(34.8)
90.1
(32.3)
82.8
(28.2)
72.7
(22.6)
65.3
(18.5)
98.1
(36.7)
Mean daily maximum °F (°C) 41.6
(5.3)
43.1
(6.2)
48.4
(9.1)
57.1
(13.9)
65.7
(18.7)
75.0
(23.9)
80.3
(26.8)
79.2
(26.2)
74.0
(23.3)
64.9
(18.3)
54.9
(12.7)
46.6
(8.1)
60.9
(16.1)
Daily mean °F (°C) 35.8
(2.1)
37.2
(2.9)
42.6
(5.9)
51.4
(10.8)
60.3
(15.7)
69.9
(21.1)
75.4
(24.1)
74.8
(23.8)
69.3
(20.7)
59.3
(15.2)
49.0
(9.4)
40.9
(4.9)
55.5
(13.1)
Mean daily minimum °F (°C) 29.9
(−1.2)
31.3
(−0.4)
36.9
(2.7)
45.6
(7.6)
54.9
(12.7)
64.8
(18.2)
70.5
(21.4)
70.3
(21.3)
64.6
(18.1)
53.6
(12.0)
43.1
(6.2)
35.1
(1.7)
50.1
(10.1)
Mean minimum °F (°C) 6.5
(−14.2)
9.7
(−12.4)
16.1
(−8.8)
26.7
(−2.9)
36.0
(2.2)
46.2
(7.9)
55.9
(13.3)
53.8
(12.1)
43.5
(6.4)
31.0
(−0.6)
20.4
(−6.4)
14.0
(−10.0)
4.4
(−15.3)
Record low °F (°C) −4
(−20)
−9
(−23)
8
(−13)
15
(−9)
33
(1)
45
(7)
52
(11)
48
(9)
37
(3)
27
(−3)
10
(−12)
−7
(−22)
−9
(−23)
Average precipitation inches (mm) 3.09
(78)
3.27
(83)
4.27
(108)
3.36
(85)
3.10
(79)
3.23
(82)
3.75
(95)
4.13
(105)
3.56
(90)
4.25
(108)
3.44
(87)
4.17
(106)
43.62
(1,108)
Average snowfall inches (cm) 5.7
(14)
5.9
(15)
2.2
(5.6)
0.3
(0.76)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.1
(0.25)
3.2
(8.1)
17.4
(43.71)
Average precipitation days (≥ 0.01 in) 9.9 9.5 10.9 10.6 10.6 9.3 9.0 7.9 8.1 8.6 8.8 10.9 114.1
Average snowy days (≥ 0.1 in) 3.0 3.2 1.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.4 8.9
Average ultraviolet index 1.6 2.6 4.2 6.0 7.5 8.5 8.6 7.7 6.0 3.8 2.1 1.5 5.0
Source 1: NOAA[8][9](snow/snow days)[10]
Source 2: UV Index Today (1995 to 2022)[11]
Climate data for Newark, New Jersey (Newark Liberty Int'l), 1991–2020 normals, extremes 1893–present
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 74
(23)
80
(27)
89
(32)
97
(36)
99
(37)
103
(39)
108
(42)
105
(41)
105
(41)
96
(36)
85
(29)
76
(24)
108
(42)
Mean maximum °F (°C) 61.8
(16.6)
62.5
(16.9)
72.3
(22.4)
84.4
(29.1)
91.4
(33.0)
95.9
(35.5)
98.7
(37.1)
95.9
(35.5)
91.5
(33.1)
82.4
(28.0)
72.2
(22.3)
63.8
(17.7)
100.0
(37.8)
Mean daily maximum °F (°C) 40.0
(4.4)
43.0
(6.1)
50.9
(10.5)
62.6
(17.0)
72.6
(22.6)
81.8
(27.7)
86.9
(30.5)
84.7
(29.3)
77.7
(25.4)
66.0
(18.9)
54.9
(12.7)
44.8
(7.1)
63.8
(17.7)
Daily mean °F (°C) 32.8
(0.4)
35.1
(1.7)
42.5
(5.8)
53.3
(11.8)
63.3
(17.4)
72.7
(22.6)
78.2
(25.7)
76.4
(24.7)
69.2
(20.7)
57.5
(14.2)
47.0
(8.3)
38.0
(3.3)
55.5
(13.1)
Mean daily minimum °F (°C) 25.5
(−3.6)
27.2
(−2.7)
34.2
(1.2)
44.1
(6.7)
53.9
(12.2)
63.6
(17.6)
69.4
(20.8)
68.0
(20.0)
60.7
(15.9)
49.0
(9.4)
39.0
(3.9)
31.2
(−0.4)
47.1
(8.4)
Mean minimum °F (°C) 9.1
(−12.7)
12.1
(−11.1)
19.4
(−7.0)
32.3
(0.2)
42.5
(5.8)
52.5
(11.4)
61.9
(16.6)
59.2
(15.1)
48.3
(9.1)
36.1
(2.3)
25.9
(−3.4)
17.2
(−8.2)
7.0
(−13.9)
Record low °F (°C) −10
(−23)
−14
(−26)
3
(−16)
13
(−11)
33
(1)
41
(5)
49
(9)
45
(7)
34
(1)
25
(−4)
12
(−11)
−13
(−25)
−14
(−26)
Average precipitation inches (mm) 3.42
(87)
2.98
(76)
4.13
(105)
3.87
(98)
3.97
(101)
4.34
(110)
4.66
(118)
4.15
(105)
3.82
(97)
3.79
(96)
3.33
(85)
4.14
(105)
46.60
(1,184)
Average snowfall inches (cm) 9.1
(23)
10.1
(26)
5.6
(14)
0.5
(1.3)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.2
(0.51)
0.6
(1.5)
5.4
(14)
31.5
(80)
Average precipitation days (≥ 0.01 in) 10.6 10.0 10.9 11.5 11.4 10.9 10.0 9.8 8.7 9.4 8.8 11.1 123.1
Average snowy days (≥ 0.1 in) 4.6 3.8 2.7 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.3 2.8 14.5
Average relative humidity (%) 65.4 63.3 59.9 57.5 62.0 63.0 63.4 66.2 67.9 66.3 66.5 66.7 64.0
Average dew point °F (°C) 19.2
(−7.1)
20.5
(−6.4)
27.1
(−2.7)
35.2
(1.8)
47.7
(8.7)
57.0
(13.9)
62.2
(16.8)
62.4
(16.9)
56.1
(13.4)
44.6
(7.0)
35.2
(1.8)
24.8
(−4.0)
41.0
(5.0)
Average ultraviolet index 2 3 4 6 7 8 8 8 6 4 2 1 5
Source 1: NOAA (relative humidity and dew point 1961-1989)[12][13][14]
Source 2: Weather Atlas (UV)[15]
Climate data for Newark
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Average sea temperature °F (°C) 41.7
(5.4)
39.7
(4.3)
40.2
(4.5)
45.1
(7.3)
52.5
(11.4)
64.5
(18.1)
72.1
(22.3)
74.1
(23.4)
70.1
(21.2)
63.0
(17.3)
54.3
(12.4)
47.2
(8.4)
55.4
(13.0)
Source: Weather Atlas[15]
Climate data for Trenton, New Jersey (Trenton–Mercer Airport) 1991–2020 normals, extremes 1865–present
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 73
(23)
78
(26)
87
(31)
93
(34)
99
(37)
100
(38)
106
(41)
105
(41)
101
(38)
94
(34)
83
(28)
76
(24)
106
(41)
Mean maximum °F (°C) 62.7
(17.1)
62.7
(17.1)
74.2
(23.4)
83.0
(28.3)
88.6
(31.4)
93.4
(34.1)
96.3
(35.7)
94.3
(34.6)
89.7
(32.1)
81.4
(27.4)
72.0
(22.2)
64.2
(17.9)
97.2
(36.2)
Mean daily maximum °F (°C) 39.7
(4.3)
42.8
(6.0)
50.8
(10.4)
62.9
(17.2)
72.4
(22.4)
81.0
(27.2)
86.0
(30.0)
84.0
(28.9)
77.1
(25.1)
65.5
(18.6)
54.5
(12.5)
44.4
(6.9)
63.4
(17.4)
Daily mean °F (°C) 32.0
(0.0)
34.3
(1.3)
41.7
(5.4)
52.5
(11.4)
62.0
(16.7)
71.0
(21.7)
76.3
(24.6)
74.4
(23.6)
67.4
(19.7)
55.7
(13.2)
45.4
(7.4)
36.8
(2.7)
54.1
(12.3)
Mean daily minimum °F (°C) 24.3
(−4.3)
25.9
(−3.4)
32.7
(0.4)
42.1
(5.6)
51.6
(10.9)
60.9
(16.1)
66.6
(19.2)
64.8
(18.2)
57.7
(14.3)
45.9
(7.7)
36.3
(2.4)
29.3
(−1.5)
44.8
(7.1)
Mean minimum °F (°C) 7.2
(−13.8)
10.0
(−12.2)
17.9
(−7.8)
29.0
(−1.7)
37.7
(3.2)
48.3
(9.1)
57.0
(13.9)
54.4
(12.4)
43.2
(6.2)
31.6
(−0.2)
21.8
(−5.7)
14.8
(−9.6)
5.1
(−14.9)
Record low °F (°C) −16
(−27)
−14
(−26)
0
(−18)
11
(−12)
31
(−1)
39
(4)
46
(8)
39
(4)
34
(1)
21
(−6)
9
(−13)
−8
(−22)
−16
(−27)
Average precipitation inches (mm) 3.29
(84)
2.63
(67)
3.97
(101)
3.63
(92)
3.99
(101)
4.25
(108)
4.39
(112)
4.22
(107)
4.09
(104)
3.79
(96)
3.18
(81)
4.04
(103)
45.47
(1,155)
Average snowfall inches (cm) 7.9
(20)
8.6
(22)
4.9
(12)
0.5
(1.3)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.1
(0.25)
0.5
(1.3)
4.3
(11)
26.8
(67.85)
Average precipitation days (≥ 0.01 in) 10.1 10.1 11.0 11.5 12.0 11.9 10.8 10.0 8.6 10.0 8.5 11.0 125.5
Average snowy days (≥ 0.1 in) 4.6 4.3 2.6 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.3 2.3 14.4
Average relative humidity (%) 65.4 61.7 58.0 57.0 62.1 66.1 66.2 68.8 69.8 68.8 66.9 66.5 64.8
Average dew point °F (°C) 21.7
(−5.7)
22.8
(−5.1)
28.1
(−2.2)
37.7
(3.2)
48.7
(9.3)
59.4
(15.2)
63.9
(17.7)
63.5
(17.5)
57.0
(13.9)
45.6
(7.6)
35.9
(2.2)
26.5
(−3.1)
42.7
(5.9)
Mean monthly sunshine hours 163.1 169.7 207.4 227.2 248.1 262.8 269.2 252.5 215.0 201.5 149.3 140.1 2,505.9
Percent possible sunshine 54 57 56 57 56 58 59 59 57 58 50 48 56
Source 1: NOAA (sun 1961–1981)[16][17][18]
Source 2: PRISM Climate Group (humidity and dew point)[19]


References

  1. ^ "Koppen Climate Classification for the Conterminous United States". Data.gov. U.S. General Services Administration. Archived from the original on 8 January 2018. Retrieved 7 January 2018.
  2. ^ Harris, Amy. "The Average Climate of New Jersey". USA Today. Retrieved 7 January 2018.
  3. ^ a b Bruce A. Scruton (August 30, 2021). "New Jersey tops list of states warming up the fastest". New Jersey Herald. Retrieved December 20, 2022.
  4. ^ a b c "New Jersey Climate Overview". Rutgers, The State University of New Jersey. Retrieved 7 January 2018.
  5. ^ a b c "State Climate Extremes Committee (SCEC) Records". The National Weather Service. Retrieved 7 January 2018.
  6. ^ Solecki, William D.; et al. (2005). "Mitigation of the heat island effect in urban New Jersey". Environmental Hazards. Informa UK Limited. 6 (1): 39–49. doi:10.1016/j.hazards.2004.12.002. ISSN 1747-7891.
  7. ^ Threadex
  8. ^ "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved August 11, 2021.
  9. ^ "Station: Atlantic City, NJ". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved August 11, 2021.
  10. ^ "U.S. Climate Normals Quick Access – Station: Atlantic City INTL AP, NJ". National Oceanic and Atmospheric Administration. Retrieved February 10, 2023.
  11. ^ "Historical UV Index Data - Atlantic City, NJ". UV Index Today. Retrieved April 22, 2023.
  12. ^ "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved August 10, 2021.
  13. ^ "Station: Newark INTL AP, NJ". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved August 10, 2021.
  14. ^ "Newark Climate Normals 1961-1990". National Oceanic and Atmospheric Administration. Retrieved August 21, 2023.
  15. ^ a b "Newark, New Jersey, USA - Monthly weather forecast and Climate data". Weather Atlas. Retrieved July 4, 2019.
  16. ^ "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved August 12, 2021.
  17. ^ "Station: Trenton Mercer CO AP, NJ". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved August 12, 2021.
  18. ^ "WMO Climate Normals for Trenton/WSO City, NJ 1961–1990". NOAA. Retrieved August 12, 2021.
  19. ^ "PRISM Climate Group, Oregon State University". www.prism.oregonstate.edu. Retrieved July 31, 2019.

Notes

  1. ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1991 to 2020.
  2. ^ The official climatology station for Atlantic City was at the Weather Bureau Office downtown from January 1874 to 15 June 1958 and Atlantic City Int'l (ACY) in Egg Harbor Township since 16 June 1958.[7] ACY's location in the Pine Barrens and distance away from the coast and urban heat island of downtown Atlantic City largely account for its markedly colder temperatures at night as compared to downtown; for example, from 1959 to 2013, there were 50 days with a low of 0 °F (−18 °C) or lower, while in the same period, the corresponding number of days at downtown was 2. The National Weather Service ceased regular snowfall observations at downtown after the winter of 1958–59.