Naplate, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.9 °C (low) to 15.9 °C (high). Annual precipitation averages 961.9 Millimeters. Naplate is located in USDA Plant Hardiness Zone 6a. 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 | -9.1 °C | -0.2 °C | 49.53 mm |
| February | -7.2 °C | 2.3 °C | 47.5 mm |
| March | -1.9 °C | 9.2 °C | 62.99 mm |
| April | 4.1 °C | 16.4 °C | 89.15 mm |
| May | 10.3 °C | 22.5 °C | 119.38 mm |
| June | 15.7 °C | 27.4 °C | 115.06 mm |
| July | 17.8 °C | 29.1 °C | 97.28 mm |
| August | 16.7 °C | 28.1 °C | 98.04 mm |
| September | 12.4 °C | 25.1 °C | 83.57 mm |
| October | 5.9 °C | 18.2 °C | 78.23 mm |
| November | -0.1 °C | 9.9 °C | 67.82 mm |
| December | -5.8 °C | 2.7 °C | 53.34 mm |
| Annual | 4.9 °C | 15.9 °C | 961.89 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 6a : -23.3°C to -20.6°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 |