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Monthly climate in Mattoon, Illinois, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Mattoon features a humid subtropical climate (Cfa).Temperatures typically range between -1 °C (30 °F) and 25 °C (78 °F) through the year, but rarely can drop to -25 °C (-12 °F) or can rise to as high as 37 °C (98 °F).The average annual precipitation amounts to about 1220 mm (48.0 inches) and receives 121 rainy days on the 1 mm (0.04 inches) threshold annually.Mattoon enjoys an average of 2960 hours of sunshine throughout the year, and daylight varies from 9 hours 25 minutes to 14 hours 53 minutes per day.

Monthly average temperatures in Mattoon, Illinois, United States §

The warmest months in Mattoon are June, July and August, with daily mean temperatures ranging from 24 to 25 °C (75 - 78 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -1 to 3 °C (30 - 37 °F) throughout the day. On average each year, Mattoon experiences 112 days above 25 °C (77.0 °F) and 90 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Mattoon, 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 19°C
(66°F)		 22°C
(72°F)		 25°C
(77°F)		 29°C
(84°F)		 35°C
(95°F)		 37°C
(98°F)		 35°C
(95°F)		 34°C
(94°F)		 33°C
(92°F)		 33°C
(92°F)		 25°C
(78°F)		 18°C
(66°F)
Mean maximum 15°C
(59°F)		 18°C
(64°F)		 21°C
(71°F)		 27°C
(82°F)		 32°C
(89°F)		 34°C
(93°F)		 34°C
(93°F)		 33°C
(91°F)		 33°C
(91°F)		 30°C
(87°F)		 21°C
(69°F)		 17°C
(64°F)
Average high 3°C
(37°F)		 5°C
(42°F)		 12°C
(53°F)		 17°C
(63°F)		 24°C
(75°F)		 29°C
(84°F)		 30°C
(86°F)		 28°C
(83°F)		 27°C
(81°F)		 20°C
(68°F)		 10°C
(51°F)		 7°C
(45°F)
Daily mean -1°C
(30°F)		 1°C
(33°F)		 7°C
(44°F)		 12°C
(53°F)		 19°C
(66°F)		 24°C
(76°F)		 25°C
(78°F)		 24°C
(75°F)		 21°C
(71°F)		 14°C
(58°F)		 6°C
(42°F)		 3°C
(37°F)
Average low -5°C
(23°F)		 -4°C
(25°F)		 2°C
(35°F)		 6°C
(44°F)		 14°C
(57°F)		 19°C
(66°F)		 21°C
(70°F)		 19°C
(66°F)		 16°C
(61°F)		 9°C
(49°F)		 1°C
(34°F)		 -2°C
(29°F)
Mean minimum -18°C
(-0°F)		 -17°C
(2°F)		 -10°C
(15°F)		 -3°C
(28°F)		 4°C
(40°F)		 14°C
(57°F)		 15°C
(59°F)		 13°C
(55°F)		 8°C
(47°F)		 -0°C
(32°F)		 -8°C
(18°F)		 -13°C
(9°F)
Minimum -25°C
(-12°F)		 -19°C
(-2°F)		 -17°C
(2°F)		 -6°C
(22°F)		 1°C
(34°F)		 10°C
(50°F)		 13°C
(55°F)		 11°C
(53°F)		 6°C
(43°F)		 -5°C
(24°F)		 -13°C
(10°F)		 -19°C
(-3°F)

Compare climate in Mattoon with other places

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

Monthly average precipitation in Mattoon, Illinois, United States §

Mattoon usually has the most precipitation in March, May and August, with an average of 12 rainy days and 128 mm (5.0 inches) of precipitation per month.The driest months in Mattoon are January, September and December. On average, 70 mm (2.8 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Mattoon, 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) 78 (3.1) 79 (3.1) 125 (4.9) 117 (4.6) 135 (5.3) 110 (4.3) 116 (4.6) 123 (4.8) 67 (2.6) 115 (4.5) 89 (3.5) 65 (2.6)
Average precipitation days (≥ 1 mm) 9 10 12 10 13 11 11 11 6 11 8 9

Monthly sunshine hours in Mattoon, Illinois, United States §

The sunniest months in Mattoon are June, July and August, when the sun shines an average of 11 hours 8 minutes a day.Least sunny months in Mattoon: January, February and December receive an average of 5 hours 9 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Mattoon, 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 116 165 211 243 287 338 355 330 291 236 196 186
Mean daily daylight hours 9h 43m 10h 43m 11h 58m 13h 16m 14h 21m 14h 53m 14h 36m 13h 38m 12h 23m 11h 6m 9h 59m 9h 25m

Solar UV radiation in Mattoon, Illinois, United States §

Mattoon experiences the highest level of ultraviolet (UV) radiation in May, June and July, when the maximum UV index can reach values of 10 - 11, which corresponds to the Very High / Extreme category of sun exposure.January, November and December are in the Moderate exposure category. In these months, the maximum values of the UV index do not exceed 4. For more detailed information, check out our hourly Mattoon UV Index data.

Average daily maximum UV levels by month for Mattoon, 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 5 6 9 10 11 10 9 8 6 4 3