Watson, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 44.3 °F (low) to 64.6 °F (high). Annual precipitation averages 44.3 Inches. Watson is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.3 °F | 37.3 °F | 2.99 in. |
| February | 24.3 °F | 42.1 °F | 2.51 in. |
| March | 33.3 °F | 53.0 °F | 3.32 in. |
| April | 43.6 °F | 65.5 °F | 4.9 in. |
| May | 54.5 °F | 75.2 °F | 4.97 in. |
| June | 63.5 °F | 84.0 °F | 5.0 in. |
| July | 66.4 °F | 87.2 °F | 4.36 in. |
| August | 64.0 °F | 86.0 °F | 2.94 in. |
| September | 55.8 °F | 80.3 °F | 3.12 in. |
| October | 44.6 °F | 68.5 °F | 3.53 in. |
| November | 34.3 °F | 53.6 °F | 3.76 in. |
| December | 26.2 °F | 41.9 °F | 2.91 in. |
| Annual | 44.3 °F | 64.6 °F | 44.31 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 |