The coldest night of the fall season so far is settling over the Northeast.
A Frost Advisory stretches from northern New York into Vermont, and separately across western Maine and northern New Hampshire, as temperatures drop to 32 degrees overnight into Tuesday.
Northern New York and Vermont: The Adirondacks and Northeast Kingdom
The NWS Burlington office has the advisory running from 2 AM to 8 AM EDT Tuesday.
In New York, that covers southern Franklin, western Clinton and western Essex counties. In Vermont, it’s Essex County.
Lake Placid, Saranac Lake, Tupper Lake, Dannemora, Ellenburg, Lunenburg and Island Pond are all inside the advisory area.
Forecasters had been flagging just how cold this particular night would get, well before the sun went down.
By afternoon, that forecast had narrowed into something more specific.
Notice the word “hollows.” Cold air is heavy, and it drains downhill overnight, pooling in low-lying valley floors. That’s exactly where the frost risk is concentrated, even as nearby ridgelines and the shores of Lake Champlain stay well above freezing.
Western Maine and New Hampshire’s North Country
The NWS Gray office has the same overnight window in effect for Northern Oxford County, Maine, and Northern and Southern Coos County, New Hampshire.
Berlin, Lancaster, Errol, Milan, Andover, Roxbury and Byron are included, along with more remote communities like Wilsons Mills, Upton, South Arm, Middle Dam, York Pond and Colebrook.
The setup is the same story on this side of the border, too: clear skies, calm winds and cold air settling into the valleys below the White Mountains.
What Frost Can Do
Frost can harm sensitive outdoor vegetation. Plants left uncovered overnight may not survive until morning.
What to Do Tonight
Time it right. The coldest air usually settles in right around sunrise, not at midnight, so there’s no rush to cover everything the moment the sun goes down. Get plants covered before bed, and leave the covers on until temperatures climb back above freezing the next morning.
Don’t forget the pipes. Outdoor faucets, hoses and irrigation lines are just as exposed as your plants are. Disconnect and drain garden hoses, and shut off and drain any spigots that aren’t insulated.
Protect what you can, while you can. Potted plants have it easiest, just move them indoors or into a garage for the night. Anything still in the ground needs a cover: a bedsheet, towel or frost cloth draped down to the soil traps enough ground heat to make a real difference. Skip the plastic sheeting directly on the leaves, though, since it conducts cold rather than blocking it.
What Comes Next
Relief is close behind. NWS Burlington says warmer temperatures return by midweek, and NWS Gray is already looking ahead to a calmer, milder stretch.
Tonight is the low point. From here, both offices are pointing toward a much more typical mid-September stretch across the Northeast.
