Ruma, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.6 °C (low) to 19.5 °C (high). Annual precipitation averages 1102.9 Millimeters. Ruma is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5 °C | 4.9 °C | 67.06 mm |
| February | -3.2 °C | 7.8 °C | 62.74 mm |
| March | 1.4 °C | 13.4 °C | 91.69 mm |
| April | 7.1 °C | 20 °C | 123.95 mm |
| May | 13.2 °C | 25.1 °C | 131.32 mm |
| June | 18.1 °C | 30 °C | 111 mm |
| July | 20.1 °C | 31.7 °C | 101.35 mm |
| August | 18.8 °C | 31.2 °C | 80.26 mm |
| September | 14.1 °C | 27.6 °C | 83.31 mm |
| October | 7.7 °C | 21.3 °C | 78.74 mm |
| November | 1.9 °C | 13.4 °C | 95.76 mm |
| December | -2.8 °C | 7.1 °C | 75.69 mm |
| Annual | 7.6 °C | 19.5 °C | 1102.87 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |