| 2023 Hardiness Zone: | Zone 7a: 0°F to 5°F | |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7a: 0°F to 5°F | |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F | |
| Average First Frost Date: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year | |
| Ecoregion: | 59c - Southern New England Coastal Plains and Hills | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 02891 - Westerly, RI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 21 | 22 | 29 | 38 | 48 | 57 | 63 | 62 | 55 | 44 | 36 | 26 | 42 |
| Avg Max Temp (°F) | 38 | 39 | 47 | 56 | 66 | 75 | 80 | 79 | 73 | 63 | 53 | 43 | 59 |
| Avg Precip (In.) | 4.39 | 3.5 | 4.54 | 4.31 | 3.81 | 3.5 | 3.16 | 3.98 | 3.91 | 3.86 | 4.59 | 4.33 | 47.88 |