Frost dates for Belfast, ME
At Belfast, the median last spring frost (32°F) is May 7 and the median first fall frost is Oct 5, for a typical growing season of 151 days. For a 90% chance that the last frost has passed, wait until May 21. Nearby ZIP codes are in USDA hardiness zones 5a to 6a.
- May 7Last spring frost (median)50% chance of 32°F after this date
- May 21Safer planting date10% chance of 32°F after this date
- Oct 5First fall frost (median)50% chance of 32°F by this date
- 151 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 | May 9 | May 21 | Jun 1 |
| 32°F | Apr 28 | May 7 | May 21 |
| 28°F | Apr 13 | Apr 27 | May 6 |
| 24°F | Apr 1 | Apr 13 | Apr 26 |
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 15 | Sep 27 | Oct 8 |
| 32°F | Sep 24 | Oct 5 | Oct 20 |
| 28°F | Oct 3 | Oct 19 | Nov 3 |
| 24°F | Oct 17 | Nov 2 | Nov 16 |
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 | 111 days | 128 days | 145 days |
| 32°F | 133 days | 151 days | 167 days |
| 28°F | 156 days | 174 days | 193 days |
| 24°F | 182 days | 202 days | 221 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 |
|---|---|---|---|
| 04915 | 5b | -15 to -10°F | 9 km |
| 04849 | 5b | -15 to -10°F | 9 km |
| 04974 | 5b | -15 to -10°F | 10 km |
| 04848 | 6a | -10 to -5°F | 12 km |
| 04952 | 5b | -15 to -10°F | 13 km |
| 04421 | 5b | -15 to -10°F | 14 km |
| 04973 | 5b | -15 to -10°F | 16 km |
| 04642 | 6a | -10 to -5°F | 16 km |
| 04981 | 5b | -15 to -10°F | 18 km |
| 04617 | 5b | -15 to -10°F | 21 km |
| 04683 | 6a | -10 to -5°F | 22 km |
| 04438 | 5a | -20 to -15°F | 23 km |
| 04951 | 5a | -20 to -15°F | 23 km |
| 04921 | 5a | -20 to -15°F | 24 km |
| 04627 | 6a | -10 to -5°F | 24 km |
| 04650 | 6a | -10 to -5°F | 24 km |
| 04986 | 5a | -20 to -15°F | 25 km |
| 04941 | 5a | -20 to -15°F | 25 km |
| 04681 | 6a | -10 to -5°F | 39 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 USC00170480, at 44.3950, -68.9892, elevation 6 m (20 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 162.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- W Rockport 1 NNW (26 km)
- E Surry (44 km)
- Bangor Intl Airport (47 km)
- Tenants Harbor (48 km)
- Waterville Trtmt Plant (55 km)
- Acadia National Park (58 km)
- Newcastle (59 km)
- Orono (61 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.