Galva, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4 °C (low) to 15.3 °C (high). Annual precipitation averages 988.1 Millimeters. Galva 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.3 °C | -1.2 °C | 45.47 mm |
| February | -8.5 °C | 1.4 °C | 48.51 mm |
| March | -2.7 °C | 8.6 °C | 62.23 mm |
| April | 3.2 °C | 15.9 °C | 101.09 mm |
| May | 10 °C | 22.2 °C | 124.46 mm |
| June | 15.4 °C | 26.9 °C | 122.94 mm |
| July | 17.2 °C | 28.6 °C | 102.11 mm |
| August | 16 °C | 27.7 °C | 93.47 mm |
| September | 11.3 °C | 24.5 °C | 99.06 mm |
| October | 4.9 °C | 17.5 °C | 72.64 mm |
| November | -1.4 °C | 9.1 °C | 63.75 mm |
| December | -7.1 °C | 1.9 °C | 52.32 mm |
| Annual | 4 °C | 15.3 °C | 988.05 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 |