Frost dates for Chatham, MA
At Chatham, the median last spring frost (32°F) is Apr 5 and the median first fall frost is Nov 15, for a typical growing season of 221 days. For a 90% chance that the last frost has passed, wait until Apr 18. Nearby ZIP codes are in USDA hardiness zone 7b.
- Apr 5Last spring frost (median)50% chance of 32°F after this date
- Apr 18Safer planting date10% chance of 32°F after this date
- Nov 15First fall frost (median)50% chance of 32°F by this date
- 221 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 7 | Apr 19 | May 2 |
| 32°F | Mar 27 | Apr 5 | Apr 18 |
| 28°F | Mar 15 | Mar 28 | Apr 6 |
| 24°F | Mar 3 | Mar 17 | Mar 31 |
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 21 | Nov 2 | Nov 15 |
| 32°F | Nov 1 | Nov 15 | Nov 30 |
| 28°F | Nov 12 | Nov 26 | Dec 12 |
| 24°F | Nov 24 | Dec 7 | Dec 28 |
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 | 178 days | 195 days | 212 days |
| 32°F | 205 days | 221 days | 241 days |
| 28°F | 226 days | 244 days | 265 days |
| 24°F | 245 days | 266 days | 287 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 02633 | 7b | 5 to 10°F | 4 km |
| 02650 | 7b | 5 to 10°F | 5 km |
| 02659 | 7b | 5 to 10°F | 6 km |
| 02646 | 7b | 5 to 10°F | 9 km |
| 02645 | 7b | 5 to 10°F | 10 km |
| 02643 | 7b | 5 to 10°F | 11 km |
| 02653 | 7b | 5 to 10°F | 13 km |
| 02671 | 7b | 5 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 USC00191386, at 41.6569, -69.9592, elevation 12 m (40 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 83.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Chatham Muni Airport (4 km)
- W Harwich (13 km)
- Hyannis Barnstable Muni Airport (27 km)
- Hyannis (29 km)
- E Sandwich (43 km)
- Nantucket Mem Airport (46 km)
- Edgartown (55 km)
- Woods Hole Golf Club (60 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.