Mark, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.7 °C (low) to 15.8 °C (high). Annual precipitation averages 931.4 Millimeters. Mark is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.5 °C | -0.5 °C | 44.7 mm |
| February | -7.5 °C | 2 °C | 44.96 mm |
| March | -2.1 °C | 8.9 °C | 61.47 mm |
| April | 3.9 °C | 16.5 °C | 86.87 mm |
| May | 10.4 °C | 22.6 °C | 113.28 mm |
| June | 15.8 °C | 27.4 °C | 110.49 mm |
| July | 17.8 °C | 29.1 °C | 98.04 mm |
| August | 16.6 °C | 28.1 °C | 99.06 mm |
| September | 11.9 °C | 25 °C | 87.88 mm |
| October | 5.6 °C | 18.1 °C | 73.66 mm |
| November | -0.7 °C | 9.6 °C | 61.72 mm |
| December | -6.2 °C | 2.4 °C | 49.28 mm |
| Annual | 4.7 °C | 15.8 °C | 931.41 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |