| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 82f - Midcoast |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 04079 - Harpswell, ME | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 11 | 14 | 24 | 34 | 43 | 53 | 58 | 57 | 49 | 38 | 30 | 18 | 36 |
| Avg Max Temp (°F) | 31 | 34 | 42 | 54 | 65 | 74 | 80 | 78 | 70 | 59 | 47 | 36 | 56 |
| Avg Precip (In.) | 4.06 | 3.36 | 4.39 | 4.33 | 3.97 | 3.58 | 3.32 | 3.13 | 3.64 | 4.19 | 4.79 | 4.36 | 47.12 |