Chester, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 9.1 °C (low) to 17.9 °C (high). Annual precipitation averages 1160.5 Millimeters. Chester is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.7 °C | 4.9 °C | 89.92 mm |
| February | -2 °C | 6.3 °C | 72.39 mm |
| March | 1.7 °C | 10.7 °C | 108.71 mm |
| April | 7.5 °C | 17.4 °C | 89.92 mm |
| May | 13 °C | 22.6 °C | 92.71 mm |
| June | 18.3 °C | 27.8 °C | 111.51 mm |
| July | 21.3 °C | 30.2 °C | 117.09 mm |
| August | 20.4 °C | 29.3 °C | 110.49 mm |
| September | 16.6 °C | 25.7 °C | 103.38 mm |
| October | 10.1 °C | 19.1 °C | 92.96 mm |
| November | 4.4 °C | 13.1 °C | 72.64 mm |
| December | 0.3 °C | 7.7 °C | 98.81 mm |
| Annual | 9.1 °C | 17.9 °C | 1160.53 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |