Newhall, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.2 °F (low) to 58.3 °F (high). Annual precipitation averages 37.5 Inches. 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 | 11.1 °F | 27.8 °F | 1.14 in. |
| February | 14.8 °F | 32.4 °F | 1.29 in. |
| March | 26.0 °F | 45.6 °F | 2.12 in. |
| April | 37.1 °F | 59.9 °F | 3.76 in. |
| May | 49.3 °F | 70.9 °F | 4.71 in. |
| June | 59.8 °F | 80.3 °F | 5.49 in. |
| July | 63.0 °F | 83.5 °F | 4.36 in. |
| August | 60.4 °F | 81.7 °F | 4.32 in. |
| September | 51.7 °F | 75.5 °F | 3.68 in. |
| October | 39.8 °F | 62.4 °F | 2.9 in. |
| November | 27.6 °F | 46.7 °F | 2.15 in. |
| December | 17.3 °F | 33.4 °F | 1.6 in. |
| Annual | 38.2 °F | 58.3 °F | 37.52 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |