Augusta, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.2 °C (low) to 13 °C (high). Annual precipitation averages 1176.8 Millimeters. Augusta 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 | -11.9 °C | -1.4 °C | 87.88 mm |
| February | -10.9 °C | 0.2 °C | 75.69 mm |
| March | -5.4 °C | 4.8 °C | 93.73 mm |
| April | 0.7 °C | 11.8 °C | 105.41 mm |
| May | 6.6 °C | 18.3 °C | 85.34 mm |
| June | 11.9 °C | 23.2 °C | 106.93 mm |
| July | 15.3 °C | 26.4 °C | 82.8 mm |
| August | 14.5 °C | 25.9 °C | 87.12 mm |
| September | 10.3 °C | 21.8 °C | 98.04 mm |
| October | 4.2 °C | 14.7 °C | 135.13 mm |
| November | -1.3 °C | 7.9 °C | 110.49 mm |
| December | -7.3 °C | 1.9 °C | 108.2 mm |
| Annual | 2.2 °C | 13 °C | 1176.76 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |