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Monthly climate in Upper Alton, Illinois, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Upper Alton features a humid subtropical climate (Cfa).Temperatures typically range between 0 °C (32 °F) and 26 °C (79 °F) through the year, but rarely can drop to -22 °C (-8 °F) or can rise to as high as 37 °C (99 °F).The average annual precipitation amounts to about 1162 mm (45.8 inches) and receives 119 rainy days on the 1 mm (0.04 inches) threshold annually.Upper Alton enjoys an average of 3014 hours of sunshine throughout the year, and daylight varies from 9 hours 27 minutes to 14 hours 51 minutes per day.

Monthly average temperatures in Upper Alton, Illinois, United States §

The warmest months in Upper Alton are June, July and August, with daily mean temperatures ranging from 24 to 26 °C (76 - 79 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 0 to 3 °C (32 - 38 °F) throughout the day. On average each year, Upper Alton experiences 118 days above 25 °C (77.0 °F) and 79 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Upper Alton, 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)		 24°C
(75°F)		 26°C
(79°F)		 30°C
(86°F)		 34°C
(94°F)		 36°C
(97°F)		 37°C
(99°F)		 35°C
(95°F)		 34°C
(94°F)		 33°C
(92°F)		 25°C
(77°F)		 21°C
(69°F)
Mean maximum 16°C
(61°F)		 19°C
(67°F)		 23°C
(74°F)		 29°C
(84°F)		 32°C
(90°F)		 34°C
(93°F)		 35°C
(96°F)		 33°C
(93°F)		 33°C
(92°F)		 31°C
(88°F)		 22°C
(71°F)		 19°C
(67°F)
Average high 4°C
(39°F)		 6°C
(43°F)		 13°C
(55°F)		 18°C
(64°F)		 24°C
(76°F)		 29°C
(85°F)		 31°C
(87°F)		 29°C
(85°F)		 28°C
(82°F)		 20°C
(68°F)		 11°C
(53°F)		 8°C
(47°F)
Daily mean -0°C
(32°F)		 1°C
(35°F)		 8°C
(46°F)		 12°C
(55°F)		 19°C
(67°F)		 25°C
(77°F)		 26°C
(79°F)		 24°C
(76°F)		 22°C
(72°F)		 15°C
(59°F)		 6°C
(44°F)		 3°C
(38°F)
Average low -4°C
(25°F)		 -3°C
(26°F)		 3°C
(38°F)		 7°C
(45°F)		 15°C
(59°F)		 20°C
(68°F)		 22°C
(71°F)		 20°C
(68°F)		 17°C
(63°F)		 10°C
(50°F)		 2°C
(35°F)		 -1°C
(30°F)
Mean minimum -17°C
(2°F)		 -16°C
(4°F)		 -9°C
(17°F)		 -1°C
(30°F)		 6°C
(44°F)		 15°C
(59°F)		 17°C
(62°F)		 14°C
(58°F)		 9°C
(49°F)		 -0°C
(32°F)		 -7°C
(19°F)		 -11°C
(12°F)
Minimum -22°C
(-8°F)		 -19°C
(-2°F)		 -17°C
(2°F)		 -5°C
(23°F)		 4°C
(39°F)		 12°C
(54°F)		 16°C
(60°F)		 12°C
(55°F)		 7°C
(44°F)		 -3°C
(26°F)		 -13°C
(8°F)		 -19°C
(-1°F)

Compare climate in Upper Alton with other places

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

Monthly average precipitation in Upper Alton, Illinois, United States §

Upper Alton usually has the most precipitation in March, April and May, with an average of 12 rainy days and 135 mm (5.3 inches) of precipitation per month.The driest months in Upper Alton are September, November and December. On average, 64 mm (2.5 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Upper Alton, 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) 73 (2.9) 78 (3.1) 132 (5.2) 123 (4.9) 150 (5.9) 101 (4.0) 96 (3.8) 119 (4.7) 67 (2.6) 100 (3.9) 70 (2.8) 54 (2.1)
Average precipitation days (≥ 1 mm) 8 10 12 11 13 11 10 11 6 11 9 7

Monthly sunshine hours in Upper Alton, Illinois, United States §

The sunniest months in Upper Alton are June, July and August, when the sun shines an average of 11 hours 5 minutes a day.Least sunny months in Upper Alton: January, February and December receive an average of 5 hours 30 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Upper Alton, 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 124 176 209 244 290 334 352 334 293 240 213 200
Mean daily daylight hours 9h 45m 10h 44m 11h 58m 13h 15m 14h 19m 14h 51m 14h 34m 13h 36m 12h 23m 11h 7m 10h 0m 9h 27m

Solar UV radiation in Upper Alton, Illinois, United States §

Upper Alton 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 Upper Alton UV Index data.

Average daily maximum UV levels by month for Upper Alton, 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 11 9 9 6 4 3