Frost dates for Trenton Mercer Co Airport, NJ
At Trenton Mercer Co Airport, the median last spring frost (32°F) is Apr 10 and the median first fall frost is Nov 1, for a typical growing season of 202 days. For a 90% chance that the last frost has passed, wait until Apr 25. Nearby ZIP codes are in USDA hardiness zones 7a to 7b.
- Apr 10Last spring frost (median)50% chance of 32°F after this date
- Apr 25Safer planting date10% chance of 32°F after this date
- Nov 1First fall frost (median)50% chance of 32°F by this date
- 202 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 10 | Apr 25 | May 11 |
| 32°F | Mar 30 | Apr 10 | Apr 25 |
| 28°F | Mar 16 | Mar 31 | Apr 12 |
| 24°F | Feb 28 | Mar 18 | Apr 1 |
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 | Oct 6 | Oct 20 | Nov 2 |
| 32°F | Oct 15 | Nov 1 | Nov 13 |
| 28°F | Oct 29 | Nov 12 | Nov 29 |
| 24°F | Nov 9 | Nov 24 | Dec 11 |
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 | 156 days | 176 days | 197 days |
| 32°F | 180 days | 202 days | 223 days |
| 28°F | 205 days | 226 days | 250 days |
| 24°F | 229 days | 251 days | 274 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 |
|---|---|---|---|
| 08628 | 7b | 5 to 10°F | 2 km |
| 18977 | 7b | 5 to 10°F | 5 km |
| 08560 | 7a | 0 to 5°F | 6 km |
| 08534 | 7a | 0 to 5°F | 6 km |
| 19067 | 7a | 0 to 5°F | 6 km |
| 18940 | 7a | 0 to 5°F | 10 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 USW00014792, at 40.2769, -74.8158, elevation 56 m (184 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 97.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Trenton State College (2 km)
- Lambertville (14 km)
- Wertsville 4 NE (20 km)
- Hightstown 2 W (21 km)
- Philadelphia/mt Holly WFO (29 km)
- Flemington 5 NNW (33 km)
- Mount Holly S Jersey Airport (37 km)
- Moorestown (39 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.