National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

Groton / New London, Groton / New London Airport (KGON)

Lat: 41.33°NLon: 72.05°WElev: 10ft.

Mostly Cloudy

74°F

23°C

Humidity 85%
Wind Speed S 6 mph
Barometer 30.23 in (1023.6 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Last update 17 Sep 11:56 am EDT
Extended Forecast for

Old Lyme CT

  • This Afternoon

    This Afternoon: Partly sunny, with a high near 75. South wind 6 to 8 mph.

    High: 75 °F

    Partly Sunny

  • Tonight

    Tonight: A chance of showers and thunderstorms before 10pm, then showers likely and possibly a thunderstorm between 10pm and 2am, then a chance of showers and thunderstorms after 2am. Mostly cloudy, with a low around 66. South wind 3 to 7 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 66 °F

    Showers
    Likely

  • Friday

    Friday: Sunny, with a high near 79. North wind 5 to 8 mph.

    High: 79 °F

    Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 52. North wind 3 to 6 mph.

    Low: 52 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 69. Northeast wind around 6 mph becoming light and variable in the afternoon.

    High: 69 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Increasing clouds, with a low around 54.

    Low: 54 °F

    Increasing
    Clouds

  • Sunday

    Sunday: Showers. High near 69. Chance of precipitation is 90%.

    High: 69 °F

    Showers

  • Sunday Night

    Sunday Night: Showers, mainly before 2am. Low around 54. Chance of precipitation is 80%.

    Low: 54 °F

    Showers

  • Monday

    Monday: A 30 percent chance of showers before 8am. Partly sunny, with a high near 69.

    High: 69 °F

    Chance
    Showers then
    Partly Sunny

Detailed Forecast

This Afternoon
Partly sunny, with a high near 75. South wind 6 to 8 mph.
Tonight
A chance of showers and thunderstorms before 10pm, then showers likely and possibly a thunderstorm between 10pm and 2am, then a chance of showers and thunderstorms after 2am. Mostly cloudy, with a low around 66. South wind 3 to 7 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Friday
Sunny, with a high near 79. North wind 5 to 8 mph.
Friday Night
Partly cloudy, with a low around 52. North wind 3 to 6 mph.
Saturday
Mostly sunny, with a high near 69. Northeast wind around 6 mph becoming light and variable in the afternoon.
Saturday Night
Increasing clouds, with a low around 54.
Sunday
Showers. High near 69. Chance of precipitation is 90%.
Sunday Night
Showers, mainly before 2am. Low around 54. Chance of precipitation is 80%.
Monday
A 30 percent chance of showers before 8am. Partly sunny, with a high near 69.
Monday Night
Mostly cloudy, with a low around 51.
Tuesday
Partly sunny, with a high near 67.
Tuesday Night
Partly cloudy, with a low around 50.
Wednesday
Mostly sunny, with a high near 68.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Old Lyme CT
 41.31°N 72.33°W (Elev. 43 ft)
Last Update:
11:11 am EDT Sep 17, 2026
Forecast Valid:
12pm EDT Sep 17, 2026-6pm EDT Sep 23, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation