Richmond, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36 °F (low) to 55.4 °F (high). Annual precipitation averages 48.8 Inches. Richmond is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.1 °F | 30.4 °F | 3.63 in. |
| February | 13.0 °F | 33.4 °F | 3.32 in. |
| March | 22.7 °F | 41.2 °F | 3.98 in. |
| April | 33.0 °F | 53.0 °F | 4.35 in. |
| May | 43.5 °F | 64.2 °F | 3.64 in. |
| June | 52.9 °F | 73.0 °F | 4.54 in. |
| July | 58.9 °F | 78.9 °F | 3.53 in. |
| August | 57.6 °F | 78.1 °F | 3.42 in. |
| September | 50.4 °F | 70.8 °F | 3.95 in. |
| October | 39.5 °F | 58.5 °F | 5.42 in. |
| November | 29.8 °F | 47.0 °F | 4.48 in. |
| December | 19.2 °F | 36.5 °F | 4.53 in. |
| Annual | 36 °F | 55.4 °F | 48.79 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |