Littleton, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.8 °F (low) to 62 °F (high). Annual precipitation averages 39.4 Inches. Littleton is located in USDA Plant Hardiness Zone 6a. 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 | 16.6 °F | 33.6 °F | 1.95 in. |
| February | 20.4 °F | 38.5 °F | 1.94 in. |
| March | 30.2 °F | 50.5 °F | 2.52 in. |
| April | 40.9 °F | 63.1 °F | 3.95 in. |
| May | 52.4 °F | 73.3 °F | 5.0 in. |
| June | 61.9 °F | 82.0 °F | 4.8 in. |
| July | 65.1 °F | 85.4 °F | 4.0 in. |
| August | 62.7 °F | 83.9 °F | 3.7 in. |
| September | 54.3 °F | 78.1 °F | 3.58 in. |
| October | 42.8 °F | 65.6 °F | 3.13 in. |
| November | 31.9 °F | 51.2 °F | 2.75 in. |
| December | 22.4 °F | 38.7 °F | 2.1 in. |
| Annual | 41.8 °F | 62 °F | 39.42 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |