Knox, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.3 °C (low) to 15.3 °C (high). Annual precipitation averages 1038.4 Millimeters. Knox 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 | -8.9 °C | -0.1 °C | 65.53 mm |
| February | -7.3 °C | 2.1 °C | 58.17 mm |
| March | -2.6 °C | 8.3 °C | 64.01 mm |
| April | 3.2 °C | 15.3 °C | 93.22 mm |
| May | 9.8 °C | 21.5 °C | 110.24 mm |
| June | 15.2 °C | 26.6 °C | 113.79 mm |
| July | 16.6 °C | 28.2 °C | 115.32 mm |
| August | 15.5 °C | 27.2 °C | 108.97 mm |
| September | 11.1 °C | 24.3 °C | 86.87 mm |
| October | 5.1 °C | 17.5 °C | 86.87 mm |
| November | -0.4 °C | 9.4 °C | 73.91 mm |
| December | -5.4 °C | 2.9 °C | 61.47 mm |
| Annual | 4.3 °C | 15.3 °C | 1038.37 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 |