Palatine, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 14.9 °C (high). Annual precipitation averages 964.2 Millimeters. Palatine is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.2 °C | -0.7 °C | 50.55 mm |
| February | -7.7 °C | 1.4 °C | 49.78 mm |
| March | -2.5 °C | 7.6 °C | 57.15 mm |
| April | 3.2 °C | 14.6 °C | 95.5 mm |
| May | 9.2 °C | 20.8 °C | 117.09 mm |
| June | 14.7 °C | 26.4 °C | 114.05 mm |
| July | 17.7 °C | 28.8 °C | 94.74 mm |
| August | 16.9 °C | 27.6 °C | 103.89 mm |
| September | 12.4 °C | 23.9 °C | 84.07 mm |
| October | 5.8 °C | 16.7 °C | 82.3 mm |
| November | -0.3 °C | 8.8 °C | 60.96 mm |
| December | -5.9 °C | 2.3 °C | 54.1 mm |
| Annual | 4.5 °C | 14.9 °C | 964.18 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 |