| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Sep. 21 - Sep. 30 |
| Average Last Frost Date: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 82c - Eastern Maine-Southern New Brunswick Plains |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 04619 - Calais, ME | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 5 | 8 | 18 | 30 | 40 | 50 | 55 | 54 | 45 | 35 | 27 | 13 | 32 |
| Avg Max Temp (°F) | 28 | 31 | 40 | 51 | 65 | 74 | 80 | 78 | 69 | 57 | 46 | 34 | 54 |
| Avg Precip (In.) | 4.19 | 3.26 | 3.93 | 3.79 | 3.82 | 3.57 | 3.29 | 3.09 | 3.76 | 4.06 | 4.52 | 4.26 | 45.55 |