Frost dates for Bath, ME
At Bath, the median last spring frost (32°F) is May 10 and the median first fall frost is Oct 6, for a typical growing season of 149 days. For a 90% chance that the last frost has passed, wait until May 23. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- May 10Last spring frost (median)50% chance of 32°F after this date
- May 23Safer planting date10% chance of 32°F after this date
- Oct 6First fall frost (median)50% chance of 32°F by this date
- 149 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 10 | May 22 | Jun 2 |
| 32°F | Apr 28 | May 10 | May 23 |
| 28°F | Apr 17 | Apr 29 | May 10 |
| 24°F | Apr 3 | Apr 12 | Apr 24 |
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 26 | Oct 7 |
| 32°F | Sep 25 | Oct 6 | Oct 21 |
| 28°F | Oct 4 | Oct 19 | Nov 3 |
| 24°F | Oct 19 | Nov 1 | Nov 14 |
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 | 110 days | 127 days | 142 days |
| 32°F | 131 days | 149 days | 167 days |
| 28°F | 154 days | 172 days | 192 days |
| 24°F | 183 days | 201 days | 217 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 |
|---|---|---|---|
| 04530 | 6a | -10 to -5°F | 5 km |
| 04008 | 5b | -15 to -10°F | 13 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 USC00170409, at 43.9317, -69.8564, elevation 8 m (25 ft).
- Data quality: Representative (10+ years), 10 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
- Brunswick NAS (7 km)
- Wiscasset Airport (12 km)
- Westport Island (13 km)
- Durham (21 km)
- Newcastle (28 km)
- Gray (32 km)
- Gardiner (33 km)
- Lewiston (34 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.