Riverwoods, 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 58.5 °F (high). Annual precipitation averages 37.9 Inches. Riverwoods 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.0 °F | 31.3 °F | 2.12 in. |
| February | 19.9 °F | 35.0 °F | 2.01 in. |
| March | 28.8 °F | 45.3 °F | 2.28 in. |
| April | 39.0 °F | 56.9 °F | 3.82 in. |
| May | 49.8 °F | 68.5 °F | 4.41 in. |
| June | 59.9 °F | 78.7 °F | 4.39 in. |
| July | 65.5 °F | 83.2 °F | 3.74 in. |
| August | 64.3 °F | 81.5 °F | 3.92 in. |
| September | 56.4 °F | 74.9 °F | 3.38 in. |
| October | 44.4 °F | 62.2 °F | 3.31 in. |
| November | 32.9 °F | 48.1 °F | 2.44 in. |
| December | 23.1 °F | 36.6 °F | 2.12 in. |
| Annual | 41.8 °F | 58.5 °F | 37.94 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 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 |