Elma, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 1.8 °C (low) to 12.8 °C (high). Annual precipitation averages 955.8 Millimeters. Elma is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14 °C | -4.6 °C | 22.1 mm |
| February | -11.8 °C | -2.2 °C | 25.91 mm |
| March | -5.2 °C | 4.9 °C | 45.21 mm |
| April | 1.3 °C | 13.4 °C | 95.5 mm |
| May | 8.1 °C | 20.2 °C | 129.79 mm |
| June | 13.9 °C | 25.5 °C | 157.48 mm |
| July | 15.8 °C | 27.3 °C | 113.79 mm |
| August | 14.3 °C | 26.2 °C | 111 mm |
| September | 9.7 °C | 22.8 °C | 101.35 mm |
| October | 2.9 °C | 15.3 °C | 76.45 mm |
| November | -3.8 °C | 6.1 °C | 42.42 mm |
| December | -10.2 °C | -1.5 °C | 34.8 mm |
| Annual | 1.8 °C | 12.8 °C | 955.8 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |