Grier City, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.7 °F (low) to 58.9 °F (high). Annual precipitation averages 54.5 Inches. Grier City is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.3 °F | 34.3 °F | 3.91 in. |
| February | 18.4 °F | 37.0 °F | 3.08 in. |
| March | 25.9 °F | 45.5 °F | 4.16 in. |
| April | 36.5 °F | 58.8 °F | 4.53 in. |
| May | 46.5 °F | 69.4 °F | 4.57 in. |
| June | 55.5 °F | 77.0 °F | 5.57 in. |
| July | 60.0 °F | 81.7 °F | 5.02 in. |
| August | 58.0 °F | 80.0 °F | 4.75 in. |
| September | 51.3 °F | 73.3 °F | 5.42 in. |
| October | 40.3 °F | 61.8 °F | 5.11 in. |
| November | 31.0 °F | 49.4 °F | 4.02 in. |
| December | 23.3 °F | 39.1 °F | 4.36 in. |
| Annual | 38.7 °F | 58.9 °F | 54.5 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |