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Monthly climate in Alton, Missouri, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Alton features a humid subtropical climate (Cfa).Temperatures typically range between 2 °C (36 °F) and 26 °C (80 °F) through the year, but rarely can drop to -22 °C (-7 °F) or can rise to as high as 38 °C (101 °F).The average annual precipitation amounts to about 1302 mm (51.3 inches) and receives 124 rainy days on the 1 mm (0.04 inches) threshold annually.Alton enjoys an average of 3028 hours of sunshine throughout the year, and daylight varies from 9 hours 40 minutes to 14 hours 36 minutes per day.

Monthly average temperatures in Alton, Missouri, United States §

The warmest months in Alton are June, July and August, with daily mean temperatures ranging from 24 to 26 °C (76 - 80 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 2 to 6 °C (36 - 42 °F) throughout the day. On average each year, Alton experiences 123 days above 25 °C (77.0 °F) and 63 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Alton, Missouri, 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 21°C
(70°F)		 26°C
(78°F)		 29°C
(85°F)		 30°C
(87°F)		 33°C
(91°F)		 38°C
(101°F)		 38°C
(100°F)		 36°C
(97°F)		 35°C
(96°F)		 33°C
(92°F)		 28°C
(83°F)		 25°C
(77°F)
Mean maximum 18°C
(64°F)		 23°C
(73°F)		 26°C
(79°F)		 28°C
(83°F)		 31°C
(87°F)		 33°C
(92°F)		 36°C
(97°F)		 35°C
(96°F)		 34°C
(93°F)		 31°C
(88°F)		 23°C
(74°F)		 21°C
(70°F)
Average high 7°C
(45°F)		 10°C
(49°F)		 15°C
(60°F)		 19°C
(67°F)		 24°C
(76°F)		 29°C
(85°F)		 32°C
(90°F)		 30°C
(87°F)		 29°C
(84°F)		 21°C
(71°F)		 14°C
(57°F)		 11°C
(52°F)
Daily mean 2°C
(36°F)		 4°C
(40°F)		 10°C
(50°F)		 13°C
(56°F)		 19°C
(67°F)		 24°C
(76°F)		 26°C
(80°F)		 25°C
(77°F)		 23°C
(73°F)		 16°C
(60°F)		 8°C
(47°F)		 6°C
(42°F)
Average low -2°C
(29°F)		 -1°C
(31°F)		 5°C
(41°F)		 8°C
(47°F)		 15°C
(59°F)		 19°C
(67°F)		 22°C
(71°F)		 20°C
(69°F)		 17°C
(64°F)		 10°C
(51°F)		 3°C
(37°F)		 1°C
(34°F)
Mean minimum -12°C
(11°F)		 -12°C
(10°F)		 -5°C
(23°F)		 -1°C
(30°F)		 7°C
(45°F)		 14°C
(58°F)		 17°C
(64°F)		 15°C
(60°F)		 10°C
(50°F)		 -0°C
(31°F)		 -5°C
(23°F)		 -8°C
(18°F)
Minimum -16°C
(3°F)		 -22°C
(-7°F)		 -12°C
(10°F)		 -4°C
(25°F)		 3°C
(37°F)		 11°C
(52°F)		 16°C
(61°F)		 14°C
(57°F)		 7°C
(46°F)		 -4°C
(24°F)		 -10°C
(14°F)		 -12°C
(11°F)

Compare climate in Alton with other places

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

Monthly average precipitation in Alton, Missouri, United States §

Alton usually has the most precipitation in March, April and May, with an average of 13 rainy days and 165 mm (6.5 inches) of precipitation per month.The driest months in Alton are July, September and November. On average, 73 mm (2.9 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Alton, Missouri, 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) 85 (3.3) 111 (4.4) 148 (5.8) 164 (6.5) 181 (7.1) 85 (3.3) 80 (3.2) 106 (4.2) 62 (2.4) 121 (4.8) 77 (3.0) 81 (3.2)
Average precipitation days (≥ 1 mm) 8 10 14 12 15 10 11 12 6 10 8 8

Monthly sunshine hours in Alton, Missouri, United States §

The sunniest months in Alton are June, July and August, when the sun shines an average of 10 hours 51 minutes a day.Least sunny months in Alton: January, February and December receive an average of 5 hours 49 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Alton, Missouri, 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 144 179 208 242 289 327 347 323 293 245 220 204
Mean daily daylight hours 9h 57m 10h 51m 11h 59m 13h 9m 14h 8m 14h 36m 14h 21m 13h 28m 12h 21m 11h 12m 10h 11m 9h 40m

Solar UV radiation in Alton, Missouri, United States §

Alton experiences the highest level of ultraviolet (UV) radiation in May, June and July, when the maximum UV index can reach values of 11 - 11, which corresponds to the 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 5. For more detailed information, check out our hourly Alton UV Index data.

Average daily maximum UV levels by month for Alton, Missouri, 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 6 7 10 11 11 11 10 9 7 5 3