Fall officially next Sunday, September 22, but Southern New England will get a taste of clear, chilly weather in the middle of next week. High pressure moving out of Canada into New England behind a departing cold front will bring dry, cool weather for the midweek. The temperature will fall into the 40s in many spots Monday night, and Tuesday night looks even cooler.
In just the right setup, the temperature may fall into the low to mid 30s in the countryside by dawn Wednesday. With high pressure parked overhead, the wind will be light and skies will be clear. The air from Eastern Canada may be dry enough to allow the temperature to fall to within a couple of degrees of freezing – chilly enough for patchy frost in protected valleys. There is no chance of frost near the coast and in the cities.
Climatologically, the protected valleys of Southern New England usually see frost before the end of September. Therefore, a chilly night is not unusual, but it always seems to get people talking about changing of the seasons.