| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°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: | 59g - Long Island Sound Coastal Lowland |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 11787 - Smithtown, NY | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 23 | 24 | 31 | 40 | 49 | 59 | 65 | 64 | 57 | 46 | 37 | 28 | 44 |
| Avg Max Temp (°F) | 39 | 40 | 49 | 59 | 70 | 78 | 83 | 82 | 75 | 64 | 54 | 43 | 61 |
| Avg Precip (In.) | 4.19 | 3.2 | 4.42 | 4.24 | 4.01 | 3.86 | 3.48 | 4.13 | 3.76 | 3.8 | 4.04 | 4.06 | 47.21 |