Martinsville, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 43.8 °F (low) to 64.2 °F (high). Annual precipitation averages 44 Inches. Martinsville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 20.8 °F | 36.8 °F | 3.01 in. |
| February | 23.6 °F | 41.8 °F | 2.52 in. |
| March | 32.7 °F | 52.7 °F | 3.2 in. |
| April | 43.2 °F | 65.4 °F | 5.0 in. |
| May | 54.0 °F | 75.0 °F | 4.65 in. |
| June | 62.8 °F | 83.6 °F | 4.89 in. |
| July | 65.6 °F | 86.8 °F | 4.26 in. |
| August | 63.5 °F | 85.7 °F | 3.01 in. |
| September | 55.6 °F | 80.3 °F | 3.06 in. |
| October | 44.2 °F | 67.9 °F | 3.7 in. |
| November | 34.0 °F | 53.2 °F | 3.78 in. |
| December | 25.7 °F | 41.3 °F | 2.9 in. |
| Annual | 43.8 °F | 64.2 °F | 43.98 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |