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Monthly climate in Keystone, Iowa, United States

Last updated: March 2, 2024

Under the Köppen–Geiger climate classification Keystone features a humid continental climate (Dfa). Temperatures typically range between -6 °C (21 °F) and 24 °C (76 °F) through the year, but rarely can drop to -33 °C (-26 °F) or can rise to as high as 36 °C (96 °F). The average annual precipitation amounts to about 1063 mm (41.8 inches) and receives 109 rainy days on the 1 mm (0.04 inches) threshold annually. Keystone enjoys an average of 2972 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 Keystone, Iowa, United States §

The warmest months in Keystone are June, July and August, with daily mean temperatures ranging from 22 to 24 °C (72 - 76 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -6 to -1 °C (21 - 30 °F) throughout the day. On average each year, Keystone experiences 89 days above 25 °C (77.0 °F) and 124 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Keystone, Iowa, 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)		 22°C
(71°F)		 23°C
(73°F)		 29°C
(84°F)		 34°C
(94°F)		 36°C
(96°F)		 34°C
(94°F)		 34°C
(93°F)		 33°C
(92°F)		 31°C
(88°F)		 24°C
(75°F)		 23°C
(73°F)
Mean maximum 9°C
(49°F)		 14°C
(57°F)		 20°C
(68°F)		 26°C
(79°F)		 32°C
(90°F)		 33°C
(92°F)		 33°C
(92°F)		 32°C
(90°F)		 32°C
(90°F)		 30°C
(86°F)		 18°C
(65°F)		 16°C
(61°F)
Average high -2°C
(29°F)		 -1°C
(31°F)		 8°C
(47°F)		 14°C
(58°F)		 21°C
(71°F)		 28°C
(82°F)		 29°C
(84°F)		 27°C
(82°F)		 25°C
(78°F)		 16°C
(61°F)		 8°C
(47°F)		 3°C
(39°F)
Daily mean -6°C
(21°F)		 -5°C
(23°F)		 3°C
(38°F)		 9°C
(48°F)		 16°C
(62°F)		 23°C
(73°F)		 24°C
(76°F)		 22°C
(72°F)		 20°C
(67°F)		 11°C
(52°F)		 3°C
(38°F)		 -1°C
(30°F)
Average low -10°C
(14°F)		 -10°C
(14°F)		 -1°C
(30°F)		 3°C
(38°F)		 11°C
(53°F)		 17°C
(64°F)		 19°C
(67°F)		 17°C
(63°F)		 14°C
(57°F)		 6°C
(44°F)		 -2°C
(29°F)		 -5°C
(23°F)
Mean minimum -25°C
(-12°F)		 -24°C
(-11°F)		 -14°C
(7°F)		 -6°C
(21°F)		 3°C
(37°F)		 12°C
(53°F)		 14°C
(58°F)		 11°C
(53°F)		 7°C
(44°F)		 -4°C
(26°F)		 -11°C
(12°F)		 -16°C
(3°F)
Minimum -32°C
(-25°F)		 -33°C
(-26°F)		 -23°C
(-8°F)		 -11°C
(13°F)		 -1°C
(31°F)		 9°C
(49°F)		 12°C
(53°F)		 10°C
(51°F)		 3°C
(37°F)		 -5°C
(23°F)		 -17°C
(1°F)		 -22°C
(-8°F)

Compare climate in Keystone with other places

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

Monthly average precipitation in Keystone, Iowa, United States §

Keystone usually has the most precipitation in May, June and October, with an average of 12 rainy days and 149 mm (5.9 inches) of precipitation per month. The driest months in Keystone are January, November and December. On average, 43 mm (1.7 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Keystone, Iowa, 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) 45 (1.8) 52 (2.1) 73 (2.9) 85 (3.3) 162 (6.4) 143 (5.6) 91 (3.6) 64 (2.5) 121 (4.8) 143 (5.6) 45 (1.8) 40 (1.6)
Average precipitation days (≥ 1 mm) 7 8 8 11 16 10 10 8 9 11 6 5

Monthly sunshine hours in Keystone, Iowa, United States §

The sunniest months in Keystone are June, July and August, when the sun shines an average of 11 hours 15 minutes a day. Least sunny months in Keystone: January, February and December receive an average of 5 hours 41 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Keystone, Iowa, 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 132 185 222 247 257 338 369 327 271 217 202 199
Mean daily daylight hours 9h 30m 10h 35m 11h 58m 13h 22m 14h 34m 15h 9m 14h 50m 13h 46m 12h 25m 11h 1m 9h 47m 9h 10m

Solar UV radiation in Keystone, Iowa, United States §

Keystone experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 9 - 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 3. For more detailed information, check out our hourly Keystone UV Index data.

Average daily maximum UV levels by month for Keystone, Iowa, 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 11 10 9 8 6 3 3

Detailed Monthly Weather Insights for Keystone, Iowa, United States

Discover in-depth weather details for every month in Keystone. Click through the links below for comprehensive overviews of temperature trends, precipitation levels, sunshine hours, and solar UV radiation specifics. Whether planning a visit or simply curious about Keystone's climate nuances, these monthly breakdowns provide the information you need for an informed understanding of what to expect throughout the year.

Each link leads to a detailed account of the typical weather conditions for that month, providing both locals and tourists with vital information to plan their daily activities, wardrobe, and travel itineraries accordingly.