Frost dates in Worcester, 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 Worcester is April 23, and the average first fall frost is October 21, from NOAA's Worcester Rgnl Airport station, 3 miles from the middle of Worcester. 1 year in 10 the last frost comes after May 5, and the first one by October 6. That leaves about 181 frost-free days. Worcester is in USDA planting zone 6a.
Weather stations around Worcester
The first row is the date most people in Worcester go by. The others show how far the dates move across the area.
| Station | Last spring frost | First fall frost | Frost-free |
|---|---|---|---|
| Worcester Rgnl Airport 3 mi away, 1,000 ft | April 23 1 in 10 after May 5 | October 21 1 in 10 by October 6 | 181 days |
| Buffumville Lake 12 mi away, 520 ft | May 1 1 in 10 after May 13 | October 10 1 in 10 by September 28 | 162 days |
| Barre Falls Dam 16 mi away, 825 ft | May 12 1 in 10 after May 28 | October 1 1 in 10 by September 18 | 142 days |
| Fitchburg Muni Airport 20 mi away, 348 ft | April 29 1 in 10 after May 13 | October 11 1 in 10 by October 1 | 165 days |
| E Brimfield Lake 20 mi away, 700 ft | April 28 1 in 10 after May 17 | October 15 1 in 10 by October 1 | 170 days |
Distances are from the middle of Worcester 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 01608, at the middle of the city.
Your exact ZIP code
Worcester 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: Boston · 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