Newhall, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.4 °C (low) to 14.6 °C (high). Annual precipitation averages 953 Millimeters. Newhall 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 | -11.6 °C | -2.3 °C | 28.96 mm |
| February | -9.6 °C | 0.2 °C | 32.77 mm |
| March | -3.3 °C | 7.6 °C | 53.85 mm |
| April | 2.8 °C | 15.5 °C | 95.5 mm |
| May | 9.6 °C | 21.6 °C | 119.63 mm |
| June | 15.4 °C | 26.8 °C | 139.45 mm |
| July | 17.2 °C | 28.6 °C | 110.74 mm |
| August | 15.8 °C | 27.6 °C | 109.73 mm |
| September | 10.9 °C | 24.2 °C | 93.47 mm |
| October | 4.3 °C | 16.9 °C | 73.66 mm |
| November | -2.4 °C | 8.2 °C | 54.61 mm |
| December | -8.2 °C | 0.8 °C | 40.64 mm |
| Annual | 3.4 °C | 14.6 °C | 953.01 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |