Bull Valley, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.8 °F (low) to 58.3 °F (high). Annual precipitation averages 38.5 Inches. Bull Valley 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 | 14.1 °F | 30.0 °F | 1.8 in. |
| February | 16.8 °F | 34.2 °F | 1.88 in. |
| March | 26.3 °F | 45.7 °F | 2.22 in. |
| April | 36.3 °F | 58.1 °F | 3.81 in. |
| May | 47.8 °F | 69.6 °F | 4.68 in. |
| June | 57.7 °F | 79.3 °F | 4.97 in. |
| July | 62.0 °F | 83.1 °F | 3.96 in. |
| August | 60.3 °F | 81.3 °F | 3.92 in. |
| September | 52.6 °F | 74.6 °F | 3.6 in. |
| October | 41.4 °F | 61.5 °F | 3.16 in. |
| November | 30.4 °F | 47.2 °F | 2.46 in. |
| December | 20.0 °F | 34.6 °F | 2.0 in. |
| Annual | 38.8 °F | 58.3 °F | 38.46 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 5b : -15°F to -10°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 |