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Monthly climate in Union, Illinois, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Union features a humid continental climate (Dfa).Temperatures typically range between -5 °C (23 °F) and 24 °C (75 °F) through the year, but rarely can drop to -34 °C (-28 °F) or can rise to as high as 34 °C (94 °F).The average annual precipitation amounts to about 1093 mm (43.0 inches) and receives 129 rainy days on the 1 mm (0.04 inches) threshold annually.Union enjoys an average of 2936 hours of sunshine throughout the year, and daylight varies from 9 hours 7 minutes to 15 hours 12 minutes per day.

Monthly average temperatures in Union, Illinois, United States §

The warmest months in Union are June, July and August, with daily mean temperatures ranging from 21 to 24 °C (71 - 75 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -5 to 0 °C (23 - 32 °F) throughout the day. On average each year, Union experiences 80 days above 25 °C (77.0 °F) and 119 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Union, Illinois, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 14°C
(57°F)		 20°C
(68°F)		 25°C
(76°F)		 28°C
(82°F)		 33°C
(92°F)		 34°C
(94°F)		 34°C
(93°F)		 34°C
(93°F)		 33°C
(92°F)		 31°C
(87°F)		 24°C
(75°F)		 19°C
(66°F)
Mean maximum 9°C
(49°F)		 13°C
(55°F)		 20°C
(68°F)		 25°C
(78°F)		 30°C
(87°F)		 32°C
(90°F)		 33°C
(92°F)		 32°C
(90°F)		 31°C
(88°F)		 29°C
(84°F)		 17°C
(63°F)		 15°C
(59°F)
Average high -1°C
(30°F)		 1°C
(33°F)		 8°C
(47°F)		 13°C
(56°F)		 20°C
(69°F)		 26°C
(80°F)		 28°C
(83°F)		 27°C
(81°F)		 24°C
(76°F)		 16°C
(61°F)		 7°C
(45°F)		 3°C
(38°F)
Daily mean -5°C
(23°F)		 -4°C
(26°F)		 3°C
(38°F)		 8°C
(47°F)		 15°C
(60°F)		 21°C
(71°F)		 24°C
(75°F)		 22°C
(72°F)		 19°C
(67°F)		 11°C
(53°F)		 3°C
(38°F)		 -0°C
(32°F)
Average low -9°C
(16°F)		 -8°C
(17°F)		 -1°C
(30°F)		 3°C
(38°F)		 11°C
(51°F)		 16°C
(62°F)		 19°C
(66°F)		 17°C
(63°F)		 14°C
(57°F)		 7°C
(45°F)		 -1°C
(30°F)		 -4°C
(25°F)
Mean minimum -24°C
(-11°F)		 -24°C
(-11°F)		 -13°C
(9°F)		 -5°C
(24°F)		 2°C
(36°F)		 12°C
(53°F)		 14°C
(57°F)		 11°C
(52°F)		 6°C
(43°F)		 -2°C
(28°F)		 -11°C
(12°F)		 -14°C
(6°F)
Minimum -32°C
(-25°F)		 -34°C
(-28°F)		 -21°C
(-6°F)		 -8°C
(17°F)		 -2°C
(29°F)		 9°C
(48°F)		 12°C
(54°F)		 8°C
(47°F)		 2°C
(35°F)		 -6°C
(22°F)		 -17°C
(2°F)		 -22°C
(-7°F)

Compare climate in Union with other places

Compare temperature, precipitation, sunshine, UV index in Union, Illinois, United States with other places around the world.

Monthly average precipitation in Union, Illinois, United States §

Union usually has the most precipitation in May, June and October, with an average of 13 rainy days and 134 mm (5.3 inches) of precipitation per month.The driest months in Union are February, November and December. On average, 54 mm (2.1 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Union, Illinois, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 61 (2.4) 59 (2.3) 72 (2.8) 112 (4.4) 162 (6.4) 119 (4.7) 92 (3.6) 92 (3.6) 99 (3.9) 121 (4.8) 51 (2.0) 53 (2.1)
Average precipitation days (≥ 1 mm) 8 10 10 13 14 14 12 11 10 13 7 7

Monthly sunshine hours in Union, Illinois, United States §

The sunniest months in Union are June, July and August, when the sun shines an average of 11 hours 6 minutes a day.Least sunny months in Union: January, February and December receive an average of 5 hours 18 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Union, Illinois, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 121 184 236 243 278 325 360 336 277 207 189 176
Mean daily daylight hours 9h 28m 10h 34m 11h 58m 13h 23m 14h 36m 15h 12m 14h 52m 13h 47m 12h 25m 11h 0m 9h 46m 9h 7m

Solar UV radiation in Union, Illinois, United States §

Union experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 9 - 10, which corresponds to the Very High category of sun exposure.January, November and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Union UV Index data.

Average daily maximum UV levels by month for Union, Illinois, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 3 4 6 8 9 10 10 9 8 5 3 2