Massachusetts frost dates by city
| City | Last frost (50%) | Safer date (10%) | First frost (50%) | Season |
|---|---|---|---|---|
| Boston | Apr 4 | Apr 17 | Nov 9 | 218 days |
| Worcester | Apr 23 | May 5 | Oct 21 | 181 days |
Each city uses its nearest major NOAA weather station, usually the airport. Valleys, hilltops and rural spots can differ from it by one to three weeks. How to read these dates.