Numa, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 15.9 °C (high). Annual precipitation averages 987.3 Millimeters. Numa is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.1 °C | -0.1 °C | 28.7 mm |
| February | -8 °C | 2.6 °C | 37.59 mm |
| March | -2.1 °C | 9.7 °C | 57.4 mm |
| April | 3.9 °C | 16.4 °C | 100.58 mm |
| May | 10.3 °C | 21.8 °C | 137.67 mm |
| June | 15.8 °C | 27.1 °C | 134.62 mm |
| July | 18.1 °C | 29.4 °C | 116.59 mm |
| August | 16.8 °C | 28.7 °C | 106.68 mm |
| September | 11.9 °C | 24.7 °C | 98.81 mm |
| October | 5.3 °C | 17.7 °C | 74.93 mm |
| November | -1.4 °C | 9.6 °C | 54.36 mm |
| December | -6.8 °C | 2.7 °C | 39.37 mm |
| Annual | 4.5 °C | 15.9 °C | 987.3 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |