Frost dates in Boston, Massachusetts
NOAA 1991–2020 normals for a 32 °F freeze. Low spots and the edge of town run colder than downtown.
Short answer
The average last spring frost in Boston is April 4, and the average first fall frost is November 9, from NOAA's Boston Logan Intl Airport station, 2 miles from the middle of Boston. 1 year in 10 the last frost comes after April 17, and the first one by October 29. That leaves about 219 frost-free days. Boston is in USDA planting zone 7a.
Weather stations around Boston
The first row is the date most people in Boston go by. The others show how far the dates move across the area.
| Station | Last spring frost | First fall frost | Frost-free |
|---|---|---|---|
| Boston Logan Intl Airport 2 mi away, 12 ft | April 4 1 in 10 after April 17 | November 9 1 in 10 by October 29 | 219 days |
| Jamaica Plain 6 mi away, 95 ft | April 19 1 in 10 after May 3 | October 23 1 in 10 by October 8 | 187 days |
| Hingham 9 mi away, 35 ft | April 25 1 in 10 after May 8 | October 22 1 in 10 by October 6 | 180 days |
| Blue Hill Coop 10 mi away, 625 ft | April 18 1 in 10 after April 30 | October 26 1 in 10 by October 9 | 191 days |
| Blue Hill 10 mi away, 625 ft | April 19 1 in 10 after May 1 | October 24 1 in 10 by October 10 | 188 days |
Distances are from the middle of Boston as the Census Bureau maps it. The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. The planting zone is the USDA 2023 zone for ZIP code 02127, at the middle of the city.
Your exact ZIP code
Boston covers a lot of ground. For the station nearest your own street, and its planting zone, type your ZIP code.
How these dates work
Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.
The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.
More frost dates
All of Massachusetts, station by station.
Other Massachusetts cities: Worcester · Springfield
Nearby: Providence, RI · Bridgeport, CT
Where the numbers come from
- USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture
- PRISM Climate Group, Oregon State University (zone data)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal
- NOAA, Normals calculation methodology (frost-freeze probability dates)
- US Census Bureau, 2025 ZCTA gazetteer (ZIP code centers)
- US Census Bureau, 2025 city population estimates and place gazetteer