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Monthly climate in Harlan, Iowa, United States

Last updated: March 2, 2024

Under the Köppen–Geiger climate classification Harlan features a humid continental climate (Dfa). Temperatures typically range between -5 °C (23 °F) and 25 °C (76 °F) through the year, but rarely can drop to -32 °C (-26 °F) or can rise to as high as 38 °C (101 °F). The average annual precipitation amounts to about 964 mm (38.0 inches) and receives 102 rainy days on the 1 mm (0.04 inches) threshold annually. Harlan enjoys an average of 3086 hours of sunshine throughout the year, and daylight varies from 9 hours 11 minutes to 15 hours 8 minutes per day.

Monthly average temperatures in Harlan, Iowa, United States §

The warmest months in Harlan are June, July and August, with daily mean temperatures ranging from 23 to 25 °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 -1 °C (23 - 30 °F) throughout the day. On average each year, Harlan experiences 93 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 Harlan, 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 12°C
(55°F)		 20°C
(69°F)		 25°C
(77°F)		 30°C
(87°F)		 35°C
(95°F)		 38°C
(101°F)		 34°C
(94°F)		 35°C
(95°F)		 35°C
(95°F)		 31°C
(88°F)		 25°C
(78°F)		 21°C
(70°F)
Mean maximum 11°C
(51°F)		 15°C
(59°F)		 21°C
(71°F)		 26°C
(80°F)		 32°C
(89°F)		 33°C
(92°F)		 34°C
(93°F)		 32°C
(90°F)		 33°C
(91°F)		 29°C
(85°F)		 19°C
(66°F)		 15°C
(59°F)
Average high -1°C
(31°F)		 0°C
(33°F)		 9°C
(49°F)		 15°C
(59°F)		 21°C
(71°F)		 29°C
(84°F)		 29°C
(85°F)		 28°C
(82°F)		 25°C
(78°F)		 16°C
(61°F)		 9°C
(48°F)		 4°C
(39°F)
Daily mean -5°C
(23°F)		 -5°C
(24°F)		 4°C
(39°F)		 9°C
(49°F)		 16°C
(61°F)		 23°C
(74°F)		 25°C
(76°F)		 23°C
(73°F)		 20°C
(68°F)		 11°C
(51°F)		 3°C
(38°F)		 -1°C
(30°F)
Average low -9°C
(16°F)		 -10°C
(15°F)		 -1°C
(31°F)		 3°C
(38°F)		 11°C
(53°F)		 18°C
(65°F)		 20°C
(68°F)		 18°C
(64°F)		 14°C
(58°F)		 6°C
(42°F)		 -2°C
(29°F)		 -6°C
(22°F)
Mean minimum -23°C
(-10°F)		 -23°C
(-8°F)		 -11°C
(12°F)		 -6°C
(21°F)		 3°C
(38°F)		 11°C
(53°F)		 14°C
(57°F)		 11°C
(53°F)		 6°C
(43°F)		 -3°C
(26°F)		 -11°C
(12°F)		 -16°C
(4°F)
Minimum -28°C
(-19°F)		 -32°C
(-26°F)		 -21°C
(-6°F)		 -11°C
(12°F)		 2°C
(35°F)		 8°C
(48°F)		 12°C
(53°F)		 10°C
(50°F)		 4°C
(40°F)		 -7°C
(20°F)		 -16°C
(3°F)		 -23°C
(-10°F)

Compare climate in Harlan with other places

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

Monthly average precipitation in Harlan, Iowa, United States §

Harlan usually has the most precipitation in May, August and October, with an average of 11 rainy days and 136 mm (5.4 inches) of precipitation per month. The driest months in Harlan are January, November and December. On average, 34 mm (1.3 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Harlan, 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) 29 (1.1) 38 (1.5) 82 (3.2) 58 (2.3) 167 (6.6) 110 (4.3) 70 (2.8) 117 (4.6) 97 (3.8) 124 (4.9) 35 (1.4) 37 (1.5)
Average precipitation days (≥ 1 mm) 5 6 9 10 16 10 8 9 10 10 5 4

Monthly sunshine hours in Harlan, Iowa, United States §

The sunniest months in Harlan are June, July and August, when the sun shines an average of 11 hours 27 minutes a day. Least sunny months in Harlan: January, February and November receive an average of 6 hours 13 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Harlan, 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 147 201 217 262 263 350 375 328 280 229 211 217
Mean daily daylight hours 9h 32m 10h 36m 11h 58m 13h 22m 14h 32m 15h 8m 14h 48m 13h 45m 12h 25m 11h 1m 9h 48m 9h 11m

Solar UV radiation in Harlan, Iowa, United States §

Harlan 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 Harlan UV Index data.

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

Detailed Monthly Weather Insights for Harlan, Iowa, United States

Discover in-depth weather details for every month in Harlan. 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 Harlan'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.