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Monthly climate in Rock Falls, Illinois, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Rock Falls features a humid continental climate (Dfa).Temperatures typically range between -5 °C (24 °F) and 24 °C (76 °F) through the year, but rarely can drop to -34 °C (-30 °F) or can rise to as high as 35 °C (95 °F).The average annual precipitation amounts to about 1114 mm (43.9 inches) and receives 120 rainy days on the 1 mm (0.04 inches) threshold annually.Rock Falls enjoys an average of 2977 hours of sunshine throughout the year, and daylight varies from 9 hours 10 minutes to 15 hours 9 minutes per day.

Monthly average temperatures in Rock Falls, Illinois, United States §

The warmest months in Rock Falls are June, July and August, with daily mean temperatures ranging from 23 to 24 °C (73 - 76 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -5 to 0 °C (24 - 32 °F) throughout the day. On average each year, Rock Falls experiences 93 days above 25 °C (77.0 °F) and 114 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Rock Falls, 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 13°C
(55°F)		 21°C
(70°F)		 25°C
(77°F)		 28°C
(84°F)		 34°C
(94°F)		 34°C
(93°F)		 34°C
(93°F)		 35°C
(94°F)		 35°C
(95°F)		 31°C
(89°F)		 24°C
(76°F)		 20°C
(69°F)
Mean maximum 9°C
(49°F)		 14°C
(58°F)		 20°C
(68°F)		 26°C
(80°F)		 31°C
(89°F)		 33°C
(91°F)		 33°C
(92°F)		 33°C
(91°F)		 32°C
(91°F)		 30°C
(86°F)		 18°C
(65°F)		 16°C
(61°F)
Average high -1°C
(30°F)		 1°C
(34°F)		 9°C
(49°F)		 15°C
(59°F)		 22°C
(71°F)		 28°C
(82°F)		 29°C
(84°F)		 28°C
(83°F)		 26°C
(78°F)		 17°C
(63°F)		 8°C
(47°F)		 4°C
(40°F)
Daily mean -5°C
(24°F)		 -3°C
(26°F)		 4°C
(40°F)		 9°C
(49°F)		 17°C
(62°F)		 23°C
(73°F)		 24°C
(76°F)		 23°C
(73°F)		 20°C
(68°F)		 12°C
(54°F)		 4°C
(39°F)		 0°C
(32°F)
Average low -9°C
(16°F)		 -8°C
(18°F)		 -0°C
(32°F)		 4°C
(40°F)		 12°C
(53°F)		 18°C
(64°F)		 20°C
(68°F)		 17°C
(64°F)		 15°C
(58°F)		 8°C
(46°F)		 -1°C
(31°F)		 -4°C
(25°F)
Mean minimum -24°C
(-10°F)		 -21°C
(-6°F)		 -11°C
(12°F)		 -5°C
(24°F)		 3°C
(38°F)		 13°C
(55°F)		 15°C
(59°F)		 12°C
(54°F)		 7°C
(45°F)		 -2°C
(29°F)		 -11°C
(13°F)		 -14°C
(7°F)
Minimum -32°C
(-25°F)		 -34°C
(-30°F)		 -20°C
(-4°F)		 -8°C
(17°F)		 -1°C
(30°F)		 9°C
(49°F)		 13°C
(56°F)		 11°C
(53°F)		 3°C
(38°F)		 -5°C
(24°F)		 -16°C
(3°F)		 -21°C
(-6°F)

Compare climate in Rock Falls with other places

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

Monthly average precipitation in Rock Falls, Illinois, United States §

Rock Falls usually has the most precipitation in May, June and September, with an average of 12 rainy days and 138 mm (5.4 inches) of precipitation per month.The driest months in Rock Falls are February, November and December. On average, 53 mm (2.1 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Rock Falls, 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) 59 (2.3) 59 (2.3) 86 (3.4) 110 (4.3) 157 (6.2) 141 (5.6) 98 (3.8) 73 (2.9) 115 (4.5) 115 (4.5) 51 (2.0) 50 (2.0)
Average precipitation days (≥ 1 mm) 8 9 10 11 16 12 11 9 10 12 6 6

Monthly sunshine hours in Rock Falls, Illinois, United States §

The sunniest months in Rock Falls are June, July and August, when the sun shines an average of 11 hours 10 minutes a day.Least sunny months in Rock Falls: January, February and December receive an average of 5 hours 34 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Rock Falls, 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 128 185 227 241 276 334 357 335 279 218 197 194
Mean daily daylight hours 9h 31m 10h 36m 11h 58m 13h 22m 14h 33m 15h 9m 14h 49m 13h 46m 12h 25m 11h 1m 9h 48m 9h 10m

Solar UV radiation in Rock Falls, Illinois, United States §

Rock Falls 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 4. For more detailed information, check out our hourly Rock Falls UV Index data.

Average daily maximum UV levels by month for Rock Falls, 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 8 9 10 10 9 8 6 4 2