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

Hazardous Weather Conditions

Current conditions at

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

Lat: 41.33°NLon: 72.05°WElev: 10ft.

Fair

84°F

29°C

Humidity 74%
Wind Speed SW 8 mph
Barometer 30.04 in (1017.0 mb)
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index92°F (33°C)
Last update 7 Aug 3:56 pm EDT
Extended Forecast for

Old Lyme CT

Heat Advisory until August 8, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory until August 8, 08:00pm

    NOW until 8:00pm Sat

    Heat Advisory

  • This Afternoon

    High: 88 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: A chance of showers and thunderstorms. Increasing clouds, with a low around 73. Light southwest wind. Chance of precipitation is 50%.

    Low: 73 °F

    Chance
    T-storms then
    Chance
    Showers

  • Saturday

    Saturday: A 30 percent chance of showers and thunderstorms, mainly after 5pm. Mostly cloudy, then gradually becoming sunny, with a high near 87. Heat index values as high as 95. Light southwest wind increasing to 5 to 9 mph in the morning.

    High: 87 °F

    Partly Sunny
    then Chance
    T-storms

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms before 11pm, then a slight chance of showers between 11pm and 2am. Partly cloudy, with a low around 73. Light southwest wind. Chance of precipitation is 30%.

    Low: 73 °F

    Chance
    T-storms then
    Slight Chance
    Showers

  • Sunday

    Sunday: Sunny, with a high near 88. West wind 3 to 8 mph.

    High: 88 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 67.

    Low: 67 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 86.

    High: 86 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 71.

    Low: 71 °F

    Partly Cloudy

Detailed Forecast

This Afternoon
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 88. Heat index values as high as 99. Southwest wind around 6 mph.
Tonight
A chance of showers and thunderstorms. Increasing clouds, with a low around 73. Light southwest wind. Chance of precipitation is 50%.
Saturday
A 30 percent chance of showers and thunderstorms, mainly after 5pm. Mostly cloudy, then gradually becoming sunny, with a high near 87. Heat index values as high as 95. Light southwest wind increasing to 5 to 9 mph in the morning.
Saturday Night
A chance of showers and thunderstorms before 11pm, then a slight chance of showers between 11pm and 2am. Partly cloudy, with a low around 73. Light southwest wind. Chance of precipitation is 30%.
Sunday
Sunny, with a high near 88. West wind 3 to 8 mph.
Sunday Night
Mostly clear, with a low around 67.
Monday
Sunny, with a high near 86.
Monday Night
Partly cloudy, with a low around 71.
Tuesday
A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 87.
Tuesday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 68.
Wednesday
Partly sunny, with a high near 84.
Wednesday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 67.
Thursday
Mostly sunny, with a high near 83.
Thursday Night
Partly cloudy, with a low around 64.
Friday
Mostly sunny, with a high near 82.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Old Lyme CT
 41.31°N 72.33°W (Elev. 43 ft)
Last Update:
3:38 pm EDT Aug 7, 2026
Forecast Valid:
4pm EDT Aug 7, 2026-6pm EDT Aug 14, 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