| 2023 Hardiness Zone: | Zone 7a: 0°F to 5°F |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°F |
| 1990 Hardiness Zone: | Zone 6b: -5F to 0F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 64a - Triassic Lowlands |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 08550 - Princeton Junction, NJ | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 21 | 23 | 31 | 39 | 49 | 58 | 64 | 62 | 54 | 43 | 35 | 27 | 42 |
| Avg Max Temp (°F) | 39 | 41 | 51 | 61 | 72 | 81 | 85 | 83 | 76 | 65 | 54 | 44 | 63 |
| Avg Precip (In.) | 3.8 | 2.86 | 3.95 | 3.9 | 4.55 | 3.76 | 5.11 | 4.35 | 4.46 | 3.53 | 3.78 | 3.79 | 47.85 |