Horsham, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45 °F (low) to 63.9 °F (high). Annual precipitation averages 48.4 Inches. Horsham is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.8 °F | 40.1 °F | 3.46 in. |
| February | 25.4 °F | 42.8 °F | 2.68 in. |
| March | 32.3 °F | 51.0 °F | 4.15 in. |
| April | 42.5 °F | 63.0 °F | 3.77 in. |
| May | 52.3 °F | 72.6 °F | 4.18 in. |
| June | 61.6 °F | 81.7 °F | 4.43 in. |
| July | 67.0 °F | 86.3 °F | 4.83 in. |
| August | 65.3 °F | 84.6 °F | 4.94 in. |
| September | 58.1 °F | 78.1 °F | 4.35 in. |
| October | 46.3 °F | 66.0 °F | 4.03 in. |
| November | 36.3 °F | 55.0 °F | 3.29 in. |
| December | 29.0 °F | 45.0 °F | 4.32 in. |
| Annual | 45 °F | 63.9 °F | 48.43 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |