Climate of Iowa
From Wikipedia, the free encyclopedia
The climate of Iowa is generally the same across the state. It has a humid continental climate according to the Köppen climate classification. Iowa has a hot summer and cold winters, while the very northeastern part has a warm summer and a cold winter.[1]
Iowa is prone to multiple types of natural disasters, including snowstorms, floods, and tornadoes.
Iowa has mostly hot summers and cold winters. The capital city of Des Moines has an average yearly temperature of 50.9 °F (10.5 °C).[2] The southern most city in Iowa, Keokuk, has an average yearly temperature of 52.1 °F (11.17 °C).[3] Northern cities in Iowa are generally colder. Mason City has an average yearly temperature of 45.6 °F (7.5 °C).[4] On average, Iowa experiences 6 days with a heat index of more than 95 °F (35 °C).[5]
| City | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Davenport[7] | 30/13 | 36/19 | 48/29 | 61/41 | 72/52 | 81/63 | 85/68 | 83/66 | 76/57 | 65/45 | 48/32 | 35/20 |
| Des Moines[8] | 31/14 | 36/19 | 49/30 | 62/41 | 72/52 | 82/62 | 86/67 | 84/65 | 76/55 | 63/43 | 48/31 | 34/18 |
| Keokuk[9] | 34/17 | 39/21 | 50/30 | 63/42 | 73/52 | 83/62 | 87/67 | 85/65 | 78/56 | 66/44 | 51/33 | 33/21 |
| Mason City[10] | 24/6 | 29/12 | 41/23 | 57/35 | 69/46 | 79/57 | 82/61 | 80/58 | 73/49 | 60/37 | 43/25 | 28/11 |
| Sioux City[11] | 31/10 | 35/15 | 47/26 | 62/37 | 73/49 | 82/59 | 86/63 | 83/63 | 76/51 | 63/38 | 46/25 | 32/13 |
Precipitation
Rain
The position of the jet stream and ocean-atmospheric oscillations greatly affect the wet and dry cycles of Iowa as it can alter temperature and precipitation across the Upper Midwest.[12] Most of the precipitation that falls in Iowa is rain associated with storms during between April through September.[12] During the summer, rainfall can exceed 13 inches (33 cm), and in northern Iowa it can exceed 14 inches (36 cm).[5]
Snow
Annual average snowfall ranges from 18–42 inches (45.72–106.68 cm) across the state. The first inch of snowfall usually occurs between November 10 – 17.[13] The most snow recorded in a single winter season was in Allerton, with around 100 inches (250 cm) of snowfall from December 2009 – February 2010.[14] The most snowfall in a single day was on April 20, 1918 in Lenox, with 24 inches (61 cm) of recorded snowfall.[15]
Drought
Drought is somewhat common in Iowa, happening around every 12 years.[16] January is the driest month of the year for Iowa.[17] Between 1640 and 1982, extreme drought conditions[a] occurred about 28 times. The longest interval of drought happened in 1664–1668.[16]
