Groton, CT Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Groton, a city in New London County, Connecticut.

Overnight

55°F

Mostly Cloudy

Mostly cloudy, with a low around 55. Northeast wind around 13 mph.

7-day forecast for Groton

When	Temp	Forecast	Wind	Precip
Overnight	55°F	Mostly Cloudy	13 mph NE	0%
Saturday	65°F	Mostly Sunny	6 to 10 mph E	0%
Saturday Night	58°F	Mostly Cloudy	8 mph SE	0%
Sunday	66°F	Showers And Thunderstorms	8 to 13 mph SE	80%
Sunday Night	61°F	Showers And Thunderstorms	9 to 14 mph E	90%
Monday	65°F	Rain Showers Likely	12 to 17 mph NE	62%
Monday Night	54°F	Slight Chance Rain Showers	10 to 16 mph NE	24%
Tuesday	62°F	Slight Chance Rain Showers	20 mph NE	20%
Tuesday Night	53°F	Mostly Cloudy	16 to 20 mph NE	11%
Wednesday	63°F	Partly Sunny then Slight Chance Rain Showers	20 to 24 mph NE	15%
Wednesday Night	53°F	Chance Rain Showers	18 to 22 mph NE	25%
Thursday	62°F	Chance Rain Showers	21 to 24 mph NE	32%
Thursday Night	53°F	Chance Rain Showers	15 to 20 mph NE	37%
Friday	66°F	Chance Rain Showers	16 to 21 mph N	34%

Forecast source: National Weather Service (api.weather.gov) for Groton (41.325, -72.067). Updated through the day.

Growing snapshot for Groton

Last spring frost

Apr 8

First fall frost

Nov 2

Growing season

207 days

Hardiness zone

More local growing data for Groton: nearby ZIP 06340 weather · frost dates · planting calendar · Connecticut frost dates

Nearby towns & communities

Baltic Colchester Conning Towers-Nautilus Park Gales Ferry Groton Long Point Jewett City Long Hill Mashantucket Mystic New London Niantic Noank Norwich Old Mystic Oxoboxo River Pawcatuck Poquonock Bridge Stonington Waterford

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Climate data from the nearest NOAA station, Groton, Ct (0.3 mi from Groton). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.