When to expect the first freeze

The weather has been somewhat boring here in New England over the past few days, with not much to talk about. I wanted to share a quick post about one of the fall firsts that excites me every year - the first freeze.

(NOAA)

This information is especially important for gardeners, who need to care for their plants. Here in New England, the median date of the first 32 °F temperature reading ranges from Nov 1-10 in far southwest Connecticut to Aug 21-31 near Mount Washington in New Hampshire. In Addison County in Vermont, the first freeze tends to occur in mid to late September.

The above climatological map was created by determining the median first date when the temperature falls below 32 °F. However, frost can occur when the temperature is 36 °F, but a hard freeze generally happens at 28 °F. I am not sure if the above map uses temperature readings at 2 meters above the surface (where the temperature is officially recorded) or at the surface. In that small difference between the ground and 2 meters above the ground, there can definitely be a temperature difference, especially at night. When gardening during the fall, it is important to err on the side of caution if the temperature looks to be nearing 35 °F overnight.