Caribou, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1 °C (low) to 10 °C (high). Annual precipitation averages 1062 Millimeters. Caribou is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -17.5 °C | -6.2 °C | 86.36 mm |
| February | -16.9 °C | -4.5 °C | 64.77 mm |
| March | -10.2 °C | 0.9 °C | 73.15 mm |
| April | -2 °C | 8.5 °C | 80.77 mm |
| May | 4.7 °C | 16.8 °C | 84.84 mm |
| June | 9.9 °C | 21.9 °C | 98.55 mm |
| July | 13.3 °C | 24.8 °C | 103.63 mm |
| August | 12.1 °C | 24.2 °C | 94.74 mm |
| September | 7.7 °C | 19.6 °C | 88.9 mm |
| October | 1.7 °C | 12.1 °C | 104.65 mm |
| November | -3.8 °C | 4.3 °C | 87.12 mm |
| December | -11.4 °C | -2.3 °C | 94.49 mm |
| Annual | -1 °C | 10 °C | 1061.97 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |