New Hartford, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.4 °F (low) to 57.4 °F (high). Annual precipitation averages 37 Inches. New Hartford 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 | 9.2 °F | 26.2 °F | 0.97 in. |
| February | 13.3 °F | 30.7 °F | 1.12 in. |
| March | 24.6 °F | 44.0 °F | 2.02 in. |
| April | 36.5 °F | 58.6 °F | 3.96 in. |
| May | 49.2 °F | 70.3 °F | 4.9 in. |
| June | 60.0 °F | 80.1 °F | 5.79 in. |
| July | 63.1 °F | 83.0 °F | 4.55 in. |
| August | 60.3 °F | 81.0 °F | 4.16 in. |
| September | 51.5 °F | 75.1 °F | 3.42 in. |
| October | 38.9 °F | 61.7 °F | 2.77 in. |
| November | 26.5 °F | 45.5 °F | 1.87 in. |
| December | 15.8 °F | 32.3 °F | 1.51 in. |
| Annual | 37.4 °F | 57.4 °F | 37.04 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |