Bangor, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.7 °F (low) to 54.5 °F (high). Annual precipitation averages 45.3 Inches. Bangor is located in USDA Plant Hardiness Zone 5a. 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 | 7.5 °F | 28.1 °F | 3.32 in. |
| February | 9.4 °F | 31.0 °F | 2.98 in. |
| March | 20.2 °F | 39.4 °F | 3.8 in. |
| April | 31.6 °F | 52.1 °F | 3.92 in. |
| May | 42.0 °F | 64.6 °F | 3.41 in. |
| June | 51.1 °F | 73.7 °F | 3.96 in. |
| July | 57.5 °F | 79.4 °F | 3.25 in. |
| August | 55.6 °F | 78.4 °F | 3.34 in. |
| September | 47.9 °F | 70.4 °F | 3.87 in. |
| October | 37.1 °F | 57.3 °F | 4.75 in. |
| November | 28.2 °F | 45.4 °F | 4.03 in. |
| December | 16.7 °F | 34.3 °F | 4.62 in. |
| Annual | 33.7 °F | 54.5 °F | 45.25 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |