Last frost* (temperature down to 32 degrees) in spring: May 31
First frost** in autumn: September 15
*The National Weather Service calculates there is a 10 per cent chance of frost occurring after this date, so be prepared to cover tender plants for a week or two after this date. If you are willing to monitor the temperature forecast daily and cover plants as needed, it is reasonably safe to set plants out up to two weeks before the “last frost” date reported here.
**The National Weather Service calculates there is a 10 per cent chance of frost occurring before this date.
Data courtesy of National Climatic Data Center, National Oceanic and Atmospheric Administration.