Itasca, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.7 °F (low) to 59.1 °F (high). Annual precipitation averages 38.8 Inches. Itasca 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 | 16.0 °F | 31.1 °F | 2.1 in. |
| February | 18.6 °F | 35.0 °F | 2.02 in. |
| March | 28.2 °F | 46.1 °F | 2.29 in. |
| April | 38.3 °F | 58.4 °F | 3.8 in. |
| May | 49.3 °F | 69.8 °F | 4.77 in. |
| June | 59.3 °F | 79.8 °F | 4.51 in. |
| July | 64.6 °F | 84.1 °F | 3.67 in. |
| August | 63.1 °F | 82.1 °F | 4.1 in. |
| September | 54.9 °F | 75.4 °F | 3.36 in. |
| October | 42.8 °F | 62.4 °F | 3.34 in. |
| November | 31.6 °F | 48.1 °F | 2.57 in. |
| December | 21.9 °F | 36.4 °F | 2.23 in. |
| Annual | 40.7 °F | 59.1 °F | 38.76 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |