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Monthly climate in Petersburg, Illinois, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Petersburg features a humid continental climate (Dfa).Temperatures typically range between -2 °C (29 °F) and 25 °C (78 °F) through the year, but rarely can drop to -27 °C (-17 °F) or can rise to as high as 35 °C (95 °F).The average annual precipitation amounts to about 1165 mm (45.9 inches) and receives 119 rainy days on the 1 mm (0.04 inches) threshold annually.Petersburg enjoys an average of 2957 hours of sunshine throughout the year, and daylight varies from 9 hours 21 minutes to 14 hours 57 minutes per day.

Monthly average temperatures in Petersburg, Illinois, United States §

The warmest months in Petersburg 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 -2 to 2 °C (29 - 36 °F) throughout the day. On average each year, Petersburg experiences 114 days above 25 °C (77.0 °F) and 94 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Petersburg, 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 17°C
(62°F)		 23°C
(74°F)		 25°C
(78°F)		 29°C
(84°F)		 35°C
(95°F)		 35°C
(95°F)		 35°C
(95°F)		 34°C
(93°F)		 35°C
(95°F)		 32°C
(90°F)		 25°C
(76°F)		 20°C
(69°F)
Mean maximum 14°C
(57°F)		 17°C
(63°F)		 21°C
(71°F)		 28°C
(83°F)		 32°C
(90°F)		 33°C
(92°F)		 34°C
(93°F)		 33°C
(91°F)		 33°C
(92°F)		 31°C
(88°F)		 20°C
(68°F)		 18°C
(65°F)
Average high 2°C
(36°F)		 4°C
(40°F)		 11°C
(53°F)		 17°C
(62°F)		 24°C
(75°F)		 29°C
(84°F)		 30°C
(86°F)		 29°C
(84°F)		 27°C
(82°F)		 19°C
(67°F)		 10°C
(51°F)		 7°C
(45°F)
Daily mean -2°C
(29°F)		 -0°C
(32°F)		 6°C
(44°F)		 11°C
(53°F)		 18°C
(66°F)		 24°C
(75°F)		 25°C
(78°F)		 24°C
(75°F)		 22°C
(71°F)		 14°C
(57°F)		 5°C
(42°F)		 2°C
(36°F)
Average low -6°C
(22°F)		 -5°C
(23°F)		 2°C
(35°F)		 6°C
(43°F)		 13°C
(57°F)		 19°C
(66°F)		 20°C
(69°F)		 18°C
(65°F)		 16°C
(61°F)		 9°C
(49°F)		 1°C
(33°F)		 -2°C
(28°F)
Mean minimum -19°C
(-2°F)		 -19°C
(-2°F)		 -10°C
(14°F)		 -3°C
(28°F)		 5°C
(41°F)		 14°C
(57°F)		 15°C
(59°F)		 13°C
(55°F)		 8°C
(47°F)		 -1°C
(31°F)		 -8°C
(18°F)		 -12°C
(10°F)
Minimum -27°C
(-17°F)		 -24°C
(-10°F)		 -18°C
(1°F)		 -7°C
(19°F)		 1°C
(33°F)		 11°C
(52°F)		 13°C
(56°F)		 11°C
(53°F)		 5°C
(42°F)		 -4°C
(25°F)		 -13°C
(8°F)		 -20°C
(-3°F)

Compare climate in Petersburg with other places

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

Monthly average precipitation in Petersburg, Illinois, United States §

Petersburg usually has the most precipitation in March, May and June, with an average of 12 rainy days and 136 mm (5.4 inches) of precipitation per month.The driest months in Petersburg are September, November and December. On average, 62 mm (2.4 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Petersburg, 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) 67 (2.6) 67 (2.6) 132 (5.2) 127 (5.0) 146 (5.7) 130 (5.1) 117 (4.6) 86 (3.4) 66 (2.6) 108 (4.3) 67 (2.6) 52 (2.0)
Average precipitation days (≥ 1 mm) 8 10 11 11 15 11 11 10 6 10 9 7

Monthly sunshine hours in Petersburg, Illinois, United States §

The sunniest months in Petersburg are June, July and August, when the sun shines an average of 11 hours 5 minutes a day.Least sunny months in Petersburg: January, February and December receive an average of 5 hours 19 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Petersburg, 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 118 171 209 237 283 337 351 331 290 231 199 194
Mean daily daylight hours 9h 40m 10h 41m 11h 58m 13h 17m 14h 24m 14h 57m 14h 39m 13h 40m 12h 23m 11h 5m 9h 56m 9h 21m

Solar UV radiation in Petersburg, Illinois, United States §

Petersburg 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 Petersburg UV Index data.

Average daily maximum UV levels by month for Petersburg, 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 7 9 10 11 11 9 8 6 4 3