Northwood, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 35.4 °F (low) to 54.6 °F (high). Annual precipitation averages 35.7 Inches. Northwood 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 | 6.5 °F | 23.3 °F | 0.99 in. |
| February | 10.4 °F | 27.7 °F | 1.03 in. |
| March | 22.7 °F | 40.2 °F | 1.94 in. |
| April | 34.7 °F | 55.7 °F | 3.74 in. |
| May | 47.0 °F | 68.0 °F | 4.9 in. |
| June | 58.0 °F | 77.8 °F | 5.27 in. |
| July | 61.3 °F | 80.9 °F | 4.62 in. |
| August | 58.6 °F | 78.5 °F | 4.2 in. |
| September | 49.9 °F | 72.4 °F | 3.43 in. |
| October | 37.3 °F | 58.8 °F | 2.58 in. |
| November | 25.1 °F | 42.7 °F | 1.69 in. |
| December | 13.5 °F | 29.0 °F | 1.29 in. |
| Annual | 35.4 °F | 54.6 °F | 35.68 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |