Union City, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.5 °F (low) to 57.6 °F (high). Annual precipitation averages 48.8 Inches. Union City 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 | 16.5 °F | 32.6 °F | 3.97 in. |
| February | 16.8 °F | 34.8 °F | 2.79 in. |
| March | 24.0 °F | 43.8 °F | 3.55 in. |
| April | 34.4 °F | 57.2 °F | 4.09 in. |
| May | 45.0 °F | 68.8 °F | 4.28 in. |
| June | 54.1 °F | 76.5 °F | 4.56 in. |
| July | 57.9 °F | 80.4 °F | 4.66 in. |
| August | 56.7 °F | 79.2 °F | 3.7 in. |
| September | 50.1 °F | 72.7 °F | 4.55 in. |
| October | 39.8 °F | 60.7 °F | 4.52 in. |
| November | 31.2 °F | 47.9 °F | 3.92 in. |
| December | 23.4 °F | 37.1 °F | 4.19 in. |
| Annual | 37.5 °F | 57.6 °F | 48.78 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 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |