Northboro, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.7 °C (low) to 16.7 °C (high). Annual precipitation averages 899.9 Millimeters. Northboro is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | 0.6 °C | 20.83 mm |
| February | -7.7 °C | 3.6 °C | 28.45 mm |
| March | -1.9 °C | 10.7 °C | 49.78 mm |
| April | 3.9 °C | 17.2 °C | 85.6 mm |
| May | 10.7 °C | 22.8 °C | 141.73 mm |
| June | 16.5 °C | 27.9 °C | 132.84 mm |
| July | 18.7 °C | 29.9 °C | 113.79 mm |
| August | 17.2 °C | 29.1 °C | 94.23 mm |
| September | 12 °C | 25.7 °C | 81.53 mm |
| October | 5.3 °C | 18.9 °C | 71.12 mm |
| November | -1.6 °C | 10.2 °C | 47.24 mm |
| December | -7.1 °C | 3.2 °C | 32.77 mm |
| Annual | 4.7 °C | 16.7 °C | 899.91 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |