Thompson, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.2 °C (low) to 13 °C (high). Annual precipitation averages 868.9 Millimeters. Thompson is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.1 °C | -4.7 °C | 22.61 mm |
| February | -11.6 °C | -2.1 °C | 23.62 mm |
| March | -4.7 °C | 4.9 °C | 47.5 mm |
| April | 1.7 °C | 13.7 °C | 90.68 mm |
| May | 8.7 °C | 20.5 °C | 121.41 mm |
| June | 14.7 °C | 25.9 °C | 133.86 mm |
| July | 16.5 °C | 27.7 °C | 113.03 mm |
| August | 15.1 °C | 26.4 °C | 100.33 mm |
| September | 10.2 °C | 23 °C | 85.09 mm |
| October | 3.3 °C | 15.6 °C | 60.2 mm |
| November | -3.6 °C | 6.2 °C | 39.37 mm |
| December | -10.3 °C | -1.5 °C | 31.24 mm |
| Annual | 2.2 °C | 13 °C | 868.94 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |