Addison, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.8 °F (low) to 59.4 °F (high). Annual precipitation averages 48.1 Inches. Addison is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.8 °F | 35.3 °F | 3.75 in. |
| February | 20.1 °F | 38.6 °F | 3.47 in. |
| March | 27.0 °F | 47.3 °F | 4.05 in. |
| April | 36.8 °F | 60.5 °F | 4.11 in. |
| May | 46.7 °F | 69.7 °F | 4.89 in. |
| June | 55.1 °F | 77.1 °F | 4.91 in. |
| July | 59.1 °F | 80.7 °F | 4.63 in. |
| August | 57.6 °F | 79.4 °F | 4.09 in. |
| September | 50.6 °F | 73.4 °F | 3.86 in. |
| October | 40.1 °F | 62.0 °F | 3.34 in. |
| November | 30.5 °F | 49.6 °F | 3.18 in. |
| December | 23.5 °F | 39.3 °F | 3.84 in. |
| Annual | 38.8 °F | 59.4 °F | 48.12 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |