Frost dates for W Harwich, MA
At W Harwich, the median last spring frost (32°F) is Apr 13 and the median first fall frost is Nov 3, for a typical growing season of 204 days. For a 90% chance that the last frost has passed, wait until Apr 26. Nearby ZIP codes are in USDA hardiness zones 7a to 7b.
- Apr 13Last spring frost (median)50% chance of 32°F after this date
- Apr 26Safer planting date10% chance of 32°F after this date
- Nov 3First fall frost (median)50% chance of 32°F by this date
- 204 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 15 | Apr 27 | May 11 |
| 32°F | Apr 2 | Apr 13 | Apr 26 |
| 28°F | Mar 18 | Apr 1 | Apr 12 |
| 24°F | Mar 5 | Mar 20 | Apr 3 |
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 8 | Oct 22 | Nov 5 |
| 32°F | Oct 22 | Nov 3 | Nov 18 |
| 28°F | Nov 2 | Nov 17 | Dec 4 |
| 24°F | Nov 16 | Dec 1 | Dec 19 |
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 | 158 days | 177 days | 197 days |
| 32°F | 186 days | 204 days | 223 days |
| 28°F | 211 days | 230 days | 251 days |
| 24°F | 236 days | 256 days | 277 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 |
|---|---|---|---|
| 02671 | 7b | 5 to 10°F | 1 km |
| 02639 | 7b | 5 to 10°F | 2 km |
| 02646 | 7b | 5 to 10°F | 4 km |
| 02670 | 7b | 5 to 10°F | 5 km |
| 02660 | 7a | 0 to 5°F | 6 km |
| 02664 | 7a | 0 to 5°F | 7 km |
| 02641 | 7b | 5 to 10°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 USC00199227, at 41.6633, -70.1161, elevation 5 m (15 ft).
- Data quality: Estimated from nearby stations (2+ years), 4 years of freeze data.
- Average days per year at or below 32°F: 94.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Chatham Muni Airport (11 km)
- Chatham (13 km)
- Hyannis Barnstable Muni Airport (14 km)
- Hyannis (16 km)
- E Sandwich (30 km)
- Edgartown (46 km)
- Nantucket Mem Airport (46 km)
- E Wareham (47 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.