Frost dates for Worcester Regional Airport, MA
At Worcester Regional Airport, the median last spring frost (32°F) is Apr 23 and the median first fall frost is Oct 21, for a typical growing season of 181 days. For a 90% chance that the last frost has passed, wait until May 5. Nearby ZIP codes are in USDA hardiness zones 6a to 6b.
- Apr 23Last spring frost (median)50% chance of 32°F after this date
- May 5Safer planting date10% chance of 32°F after this date
- Oct 21First fall frost (median)50% chance of 32°F by this date
- 181 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 23 | May 4 | May 19 |
| 32°F | Apr 11 | Apr 23 | May 5 |
| 28°F | Apr 1 | Apr 11 | Apr 22 |
| 24°F | Mar 19 | Apr 2 | Apr 12 |
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 28 | Oct 9 | Oct 23 |
| 32°F | Oct 6 | Oct 21 | Nov 3 |
| 28°F | Oct 17 | Nov 1 | Nov 15 |
| 24°F | Oct 31 | Nov 12 | Nov 29 |
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 | 139 days | 158 days | 175 days |
| 32°F | 160 days | 181 days | 198 days |
| 28°F | 185 days | 205 days | 222 days |
| 24°F | 206 days | 225 days | 245 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 |
|---|---|---|---|
| 01602 | 6b | -5 to 0°F | 2 km |
| 01611 | 6b | -5 to 0°F | 3 km |
| 01603 | 6a | -10 to -5°F | 4 km |
| 01609 | 6b | -5 to 0°F | 4 km |
| 01524 | 6b | -5 to 0°F | 5 km |
| 01612 | 6a | -10 to -5°F | 5 km |
| 01610 | 6a | -10 to -5°F | 6 km |
| 01608 | 6a | -10 to -5°F | 6 km |
| 01520 | 6b | -5 to 0°F | 7 km |
| 01605 | 6a | -10 to -5°F | 7 km |
| 01542 | 6b | -5 to 0°F | 8 km |
| 01606 | 6b | -5 to 0°F | 8 km |
| 01501 | 6a | -10 to -5°F | 8 km |
| 01607 | 6a | -10 to -5°F | 9 km |
| 01604 | 6a | -10 to -5°F | 9 km |
| 01562 | 6a | -10 to -5°F | 10 km |
| 01522 | 6a | -10 to -5°F | 12 km |
| 01527 | 6a | -10 to -5°F | 12 km |
| 01545 | 6a | -10 to -5°F | 13 km |
| 01583 | 6a | -10 to -5°F | 14 km |
| 01536 | 6b | -5 to 0°F | 15 km |
| 01535 | 6a | -10 to -5°F | 16 km |
| 01505 | 6a | -10 to -5°F | 16 km |
| 01519 | 6b | -5 to 0°F | 18 km |
| 01560 | 6b | -5 to 0°F | 20 km |
| 01532 | 6b | -5 to 0°F | 20 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 USW00094746, at 42.2706, -71.8731, elevation 305 m (1,000 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 130.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Buffumville Lake (17 km)
- Barre Falls Dam (22 km)
- E Brimfield Lake (27 km)
- Southbridge 3 SW (29 km)
- Fitchburg Muni Airport (33 km)
- Ashburnham (39 km)
- Fitchburg COOP (39 km)
- Belchertown (39 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.