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

Areas of Showers and Thunderstorms to Start the Work Week

Areas of rain and thunderstorms are forecast Monday across the central and eastern states. Some mixed rain and snow is possible in the high Sierra Mountains. Heavy to excessive rain may bring flooding in the central Appalachians. Read More >

Current conditions at

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

Lat: 41.33°NLon: 72.05°WElev: 10ft.

Overcast

60°F

16°C

Humidity 96%
Wind Speed N 14 mph
Barometer 29.96 in (1014.4 mb)
Dewpoint 59°F (15°C)
Visibility 10.00 mi
Last update 21 Sep 4:56 am EDT
Extended Forecast for

Old Lyme CT

  • Overnight

    Overnight: A 20 percent chance of rain. Cloudy, with a steady temperature around 59. North wind around 8 mph.

    Low: 59 °F

    Slight Chance
    Rain

  • Monday

    Monday: Cloudy, then gradually becoming mostly sunny, with a high near 70. Northeast wind 10 to 14 mph.

    High: 70 °F

    Decreasing
    Clouds

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 53. Northeast wind around 8 mph.

    Low: 53 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: A 20 percent chance of rain before 11am. Cloudy, then gradually becoming mostly sunny, with a high near 65. Northeast wind around 13 mph.

    High: 65 °F

    Slight Chance
    Rain then
    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 49. Northeast wind 9 to 13 mph, with gusts as high as 24 mph.

    Low: 49 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Partly sunny, with a high near 67.

    High: 67 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 49.

    Low: 49 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 67.

    High: 67 °F

    Mostly Cloudy

  • Thursday Night

    Thursday Night: A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 49.

    Low: 49 °F

    Mostly Cloudy
    then Chance
    Showers

Detailed Forecast

Overnight
A 20 percent chance of rain. Cloudy, with a steady temperature around 59. North wind around 8 mph.
Monday
Cloudy, then gradually becoming mostly sunny, with a high near 70. Northeast wind 10 to 14 mph.
Monday Night
Mostly cloudy, with a low around 53. Northeast wind around 8 mph.
Tuesday
A 20 percent chance of rain before 11am. Cloudy, then gradually becoming mostly sunny, with a high near 65. Northeast wind around 13 mph.
Tuesday Night
Mostly cloudy, with a low around 49. Northeast wind 9 to 13 mph, with gusts as high as 24 mph.
Wednesday
Partly sunny, with a high near 67.
Wednesday Night
Mostly cloudy, with a low around 49.
Thursday
Mostly cloudy, with a high near 67.
Thursday Night
A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 49.
Friday
A 50 percent chance of showers. Mostly cloudy, with a high near 65. Breezy.
Friday Night
A 50 percent chance of showers. Mostly cloudy, with a low around 51. Breezy.
Saturday
A 50 percent chance of showers. Mostly cloudy, with a high near 65. Breezy.
Saturday Night
A 40 percent chance of showers. Mostly cloudy, with a low around 51.
Sunday
Partly sunny, with a high near 67.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Old Lyme CT
 41.31°N 72.36°W (Elev. 30 ft)
Last Update:
3:38 am EDT Sep 21, 2026
Forecast Valid:
5am EDT Sep 21, 2026-6pm EDT Sep 27, 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