Frost dates for Somerville 4 NW, NJ
At Somerville 4 NW, the median last spring frost (32°F) is Apr 30 and the median first fall frost is Oct 20, for a typical growing season of 172 days. For a 90% chance that the last frost has passed, wait until May 14. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 30Last spring frost (median)50% chance of 32°F after this date
- May 14Safer planting date10% chance of 32°F after this date
- Oct 20First fall frost (median)50% chance of 32°F by this date
- 172 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 27 | May 10 | May 24 |
| 32°F | Apr 15 | Apr 30 | May 14 |
| 28°F | Apr 1 | Apr 15 | May 1 |
| 24°F | Mar 16 | Apr 1 | Apr 15 |
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 28 | Oct 9 | Oct 24 |
| 32°F | Oct 5 | Oct 20 | Nov 3 |
| 28°F | Oct 15 | Oct 31 | Nov 12 |
| 24°F | Oct 28 | Nov 10 | Nov 26 |
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 | 132 days | 150 days | 171 days |
| 32°F | 151 days | 172 days | 193 days |
| 28°F | 176 days | 198 days | 217 days |
| 24°F | 202 days | 224 days | 245 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 |
|---|---|---|---|
| 08807 | 7a | 0 to 5°F | 4 km |
| 08876 | 7a | 0 to 5°F | 4 km |
| 08869 | 7a | 0 to 5°F | 5 km |
| 08836 | 7a | 0 to 5°F | 8 km |
| 08835 | 7a | 0 to 5°F | 10 km |
| 07939 | 7a | 0 to 5°F | 10 km |
| 08890 | 7a | 0 to 5°F | 11 km |
| 08805 | 7a | 0 to 5°F | 11 km |
| 07920 | 7a | 0 to 5°F | 11 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 USC00288194, at 40.6153, -74.6531, elevation 41 m (134 ft).
- Data quality: Representative (10+ years), 15 years of freeze data.
- Average days per year at or below 32°F: 137.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Somerville Somerset Airport (2 km)
- Flemington 5 NNW (20 km)
- Wertsville 4 NE (21 km)
- Plainfield (21 km)
- New Brunswick 3 SE (25 km)
- Cranford (28 km)
- Canoe Brook (29 km)
- Boonton 1 SE (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.