Frost dates for Somerville Somerset Airport, NJ
At Somerville Somerset Airport, the median last spring frost (32°F) is Apr 26 and the median first fall frost is Oct 18, for a typical growing season of 176 days. For a 90% chance that the last frost has passed, wait until May 13. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 26Last spring frost (median)50% chance of 32°F after this date
- May 13Safer planting date10% chance of 32°F after this date
- Oct 18First fall frost (median)50% chance of 32°F by this date
- 176 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 23 | May 7 | May 23 |
| 32°F | Apr 11 | Apr 26 | May 13 |
| 28°F | Mar 28 | Apr 11 | Apr 28 |
| 24°F | Mar 14 | Mar 30 | Apr 13 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Sep 27 | Oct 7 | Oct 21 |
| 32°F | Oct 5 | Oct 18 | Nov 2 |
| 28°F | Oct 14 | Oct 30 | Nov 13 |
| 24°F | Oct 26 | Nov 11 | Nov 30 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 133 days | 152 days | 173 days |
| 32°F | 153 days | 176 days | 198 days |
| 28°F | 179 days | 202 days | 223 days |
| 24°F | 205 days | 226 days | 250 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 07921 | 7a | 0 to 5°F | 4 km |
| 08889 | 7a | 0 to 5°F | 7 km |
| 07931 | 7a | 0 to 5°F | 8 km |
| 08858 | 7a | 0 to 5°F | 9 km |
| 07977 | 7a | 0 to 5°F | 10 km |
| 07979 | 7a | 0 to 5°F | 11 km |
| 07934 | 7a | 0 to 5°F | 12 km |
| 07924 | 6b | -5 to 0°F | 13 km |
| 07830 | 6b | -5 to 0°F | 15 km |
| 07930 | 6b | -5 to 0°F | 18 km |
| 07945 | 6b | -5 to 0°F | 18 km |
| 07853 | 6b | -5 to 0°F | 21 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00054785, at 40.6239, -74.6694, elevation 32 m (105 ft).
- Data quality: Representative (10+ years), 20 years of freeze data.
- Average days per year at or below 32°F: 124.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Somerville 4 NW (2 km)
- Flemington 5 NNW (19 km)
- Wertsville 4 NE (21 km)
- Plainfield (23 km)
- New Brunswick 3 SE (27 km)
- Cranford (30 km)
- Canoe Brook (30 km)
- Lambertville (38 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.