Brewer, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1 °C (low) to 12.6 °C (high). Annual precipitation averages 1143.5 Millimeters. Brewer 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 | -13.6 °C | -2.1 °C | 84.33 mm |
| February | -12.4 °C | -0.4 °C | 74.93 mm |
| March | -6.4 °C | 4.2 °C | 95.5 mm |
| April | -0.2 °C | 11.2 °C | 98.55 mm |
| May | 5.6 °C | 18.1 °C | 86.36 mm |
| June | 10.5 °C | 23.2 °C | 100.33 mm |
| July | 14.1 °C | 26.4 °C | 82.3 mm |
| August | 13.1 °C | 25.8 °C | 84.58 mm |
| September | 8.8 °C | 21.3 °C | 97.79 mm |
| October | 2.8 °C | 14.1 °C | 120.14 mm |
| November | -2.1 °C | 7.5 °C | 102.11 mm |
| December | -8.4 °C | 1.3 °C | 116.59 mm |
| Annual | 1 °C | 12.6 °C | 1143.51 mm |
| 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 : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |