Gladstone, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.7 °C (low) to 16.1 °C (high). Annual precipitation averages 954 Millimeters. Gladstone is located in USDA Plant Hardiness Zone 6a. 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 | -9 °C | 0 °C | 37.08 mm |
| February | -6.9 °C | 2.5 °C | 45.21 mm |
| March | -0.9 °C | 9.4 °C | 61.21 mm |
| April | 5.1 °C | 16.7 °C | 96.01 mm |
| May | 11.7 °C | 22.6 °C | 127.51 mm |
| June | 17.1 °C | 27.7 °C | 117.6 mm |
| July | 19 °C | 29.7 °C | 101.6 mm |
| August | 17.8 °C | 28.7 °C | 94.23 mm |
| September | 13.2 °C | 25.3 °C | 92.96 mm |
| October | 6.6 °C | 18.2 °C | 72.9 mm |
| November | 0.1 °C | 9.9 °C | 62.23 mm |
| December | -5.6 °C | 2.9 °C | 45.47 mm |
| Annual | 5.7 °C | 16.1 °C | 954.01 mm |
| 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 6a : -23.3°C to -20.6°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 |