Phillipstown, Illinois has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.6 °C (low) to 19.1 °C (high). Annual precipitation averages 1169.4 Millimeters. Phillipstown is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.6 °C | 4.5 °C | 89.92 mm |
| February | -3.1 °C | 7.3 °C | 72.9 mm |
| March | 1.4 °C | 12.9 °C | 106.17 mm |
| April | 7.2 °C | 19.6 °C | 121.16 mm |
| May | 13.2 °C | 24.9 °C | 133.35 mm |
| June | 17.9 °C | 29.7 °C | 112.78 mm |
| July | 19.6 °C | 31.1 °C | 105.92 mm |
| August | 18.4 °C | 30.5 °C | 78.23 mm |
| September | 14.2 °C | 27.7 °C | 81.53 mm |
| October | 7.7 °C | 21.1 °C | 85.34 mm |
| November | 1.8 °C | 13.1 °C | 95.5 mm |
| December | -2.4 °C | 6.9 °C | 86.61 mm |
| Annual | 7.6 °C | 19.1 °C | 1169.41 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |