NWS Forecast for Groton CT

National Weather Service Forecast for: Groton CT
Issued by: National Weather Service New York, NY

Updated: 9:10 pm EDT Sep 12, 2026

Tonight Chance Showers	Sunday Heavy Rain	Sunday Night Chance Showers	Monday Chance Showers then Sunny	Monday Night Clear	Tuesday Sunny	Tuesday Night Mostly Clear	Wednesday Sunny	Wednesday Night Mostly Clear
Lo 66 °F	Hi 72 °F	Lo 66 °F	Hi 69 °F	Lo 55 °F	Hi 68 °F	Lo 53 °F	Hi 73 °F	Lo 59 °F

Hazardous Weather Outlook
Flood Watch

Tonight	A 30 percent chance of showers and thunderstorms after 5am. Mostly cloudy, with a low around 66. Southeast wind 3 to 5 mph.
Sunday	Showers and thunderstorms before 2pm, then showers likely between 2pm and 5pm. Some of the storms could produce heavy rainfall. High near 72. Southeast wind 6 to 8 mph becoming northeast in the afternoon. Chance of precipitation is 100%. New rainfall amounts between 2 and 3 inches possible.
Sunday Night	A 30 percent chance of showers, mainly after 5am. Mostly cloudy, with a low around 66. Calm wind becoming west around 5 mph after midnight.
Monday	A 30 percent chance of showers before 11am. Mostly cloudy through mid morning, then gradual clearing, with a steady temperature around 69. Northwest wind 11 to 13 mph.
Monday Night	Clear, with a low around 55. North wind around 8 mph.
Tuesday	Sunny, with a high near 68.
Tuesday Night	Mostly clear, with a low around 53.
Wednesday	Sunny, with a high near 73.
Wednesday Night	Mostly clear, with a low around 59.
Thursday	Mostly sunny, with a high near 77.
Thursday Night	Partly cloudy, with a low around 62.
Friday	A 30 percent chance of showers. Partly sunny, with a high near 77.
Friday Night	A 30 percent chance of showers. Mostly cloudy, with a low around 56.
Saturday	Mostly sunny, with a high near 72.

Forecast from NOAA-NWS for Groton CT.