Dongola, Illinois has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.4 °C (low) to 19.7 °C (high). Annual precipitation averages 1266.2 Millimeters. Dongola is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.7 °C | 5.8 °C | 93.98 mm |
| February | -2 °C | 8.7 °C | 87.38 mm |
| March | 2.5 °C | 14 °C | 118.87 mm |
| April | 8.1 °C | 20.3 °C | 136.65 mm |
| May | 13.8 °C | 25.1 °C | 137.92 mm |
| June | 18.4 °C | 29.7 °C | 115.06 mm |
| July | 20.4 °C | 31.3 °C | 99.31 mm |
| August | 19.1 °C | 30.8 °C | 76.2 mm |
| September | 14.6 °C | 27.7 °C | 86.61 mm |
| October | 8.1 °C | 21.7 °C | 97.03 mm |
| November | 2.6 °C | 14 °C | 113.54 mm |
| December | -1.6 °C | 7.8 °C | 103.63 mm |
| Annual | 8.4 °C | 19.7 °C | 1266.18 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| 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 | Cfa - Humid Subtropical Climate |