| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 7a: 0°F to 5°F |
| 1990 Hardiness Zone: | Zone 6b: -5F to 0F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | Apr. 21 - Apr. 30 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 84a - Cape Cod and Islands |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 11742 - Holtsville, NY | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 22 | 24 | 31 | 39 | 49 | 58 | 65 | 64 | 56 | 45 | 36 | 28 | 43 |
| Avg Max Temp (°F) | 39 | 41 | 49 | 59 | 69 | 78 | 83 | 82 | 75 | 64 | 53 | 44 | 61 |
| Avg Precip (In.) | 4.39 | 3.54 | 4.53 | 4.33 | 4.02 | 4.07 | 3.28 | 4.44 | 3.82 | 3.85 | 4.22 | 4.28 | 48.78 |