Water Temperature of the Thames River in Groton, CT

Current Water Temperature

70.9°F

Measurement Time: Tuesday, July 21, 2026, 4:30 AM EDT

Temperature Locations

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Local Points of Interest

New London, CT

Thames River

Station Name: THAMES R AT GROTON, CT.
Data Source: Water Data - usgc.gov

Elevation Above Sea Level: 10 feet

Nearest Address:
515 Thames St
Groton, CT 06340
New London County

GPS Coordinates: 41.34870948, -72.0820204

Nearby Water Temperatures

Thames River, New London, CT (1.7 mi)
Mystic River, Noank, CT (5.3 mi)
Mystic Harbor, Mystic, CT (5.9 mi)
Mystic River, Mystic, CT (6 mi)
Mystic River, Old Mystic, CT (6.5 mi)
Pawcatuck River, Westerly, RI (13.1 mi)
Connecticut River, Old Lyme, CT (13.9 mi)
East Branch Eightmile River, Lyme, CT (14.2 mi)
Eightmile River, East Haddam, CT (14.5 mi)
Yantic River, Norwich, CT (14.7 mi)
Orient Harbor, Orient, NY (18.7 mi)
Fort Pond Bay, Montauk, NY (21.7 mi)
Connecticut River, Middletown, CT (27.8 mi)
Natchaug River, Chaplin, CT (32.3 mi)
Hemlock Brook, Foster, RI (36.4 mi)

Weather for Groton, Connecticut

Current Weather

68.4°F
Mist
Mist
53.8°F
68.4°F
94%
NE 13 mph
21.8 mph
68.4°F
66.6°F
0 in
25%
6 mi
1006 mbar
0.2

Five Day Weather Forecast

Patchy rain nearby
Thu
H: 73°F
L: 64°F
Patchy rain nearby
Fri
H: 74°F
L: 62°F
Sunny
Sat
H: 77°F
L: 67°F
Partly Cloudy
Sun
H: 77°F
L: 69°F
Light rain shower
Mon
H: 74°F
L: 65°F

Air Quality

AQI: 1 - Good
PM2.5: 14.5 μg/m3
PM10: 18.3 μg/m3
Carbon Monoxide: 111 μg/m3
Nitrogen Dioxide: 6.5 μg/m3
Sulphur Dioxide: 1.3 μg/m3
Ozone: 110 μg/m3

Astronomical

Sunrise: 5:41 AM
Sun Transit: 12:54 AM
Sunset: 8:08 PM
Daylight: 14 hrs 26 mins
Moonrise: 8:51 PM
Moon Transit: 1:24 AM
Moonset: 6:31 AM
Moon Phase: Full
Moon Illumination: 97.1%

Best Times for Fishing or Hunting

Major Periods

12:54 AM - 3:24 AM
3:44 PM - 6:14 PM

Minor Periods

8:21 PM - 9:51 PM
6:01 AM - 7:31 AM

Action Rating: 5 out of 5

Small Craft Advisory issued July 29 at 3:35PM EDT until July 30 at 6:00AM EDT by NWS Upton NY

Effective: Wed July 29, 2026, 3:35 PM
Expires: Thu July 30, 2026, 5:00 AM

* WHAT...Seas 4 to 6 feet. * WHERE...Moriches Inlet NY to Montauk Point NY out 20 NM. * WHEN...Until 6 AM EDT Thursday. * IMPACTS...Conditions will be hazardous to small craft.

Inexperienced mariners, especially those operating smaller vessels, should avoid navigating in hazardous conditions.
Thursday, July 30, 2026

Weather Forecast

Patchy rain nearby
73°F
64.3°F
68.6°F
90%
0.03 in
61%
0%
14.3 mph
1.6


Air Quality

AQI: 1 - Good
PM2.5: 10.37 μg/m3
PM10: 12.63 μg/m3
Carbon Monoxide: 120.63 μg/m3
Nitrogen Dioxide: 5.02 μg/m3
Sulphur Dioxide: 0.98 μg/m3
Ozone: 108.08 μg/m3

Astronomical

Sunrise: 5:41 AM
Sun Transit: 12:54 AM
Sunset: 8:08 PM
Daylight: 14 hrs 26 mins
Moonrise: 8:51 PM
Moon Transit: 1:24 AM
Moonset: 6:31 AM
Moon Phase: Full
Moon Illumination: 97.1%

Best Times for Fishing or Hunting

Major Periods

12:54 AM - 3:24 AM
3:44 PM - 6:14 PM

Minor Periods

8:21 PM - 9:51 PM
6:01 AM - 7:31 AM

Action Rating: 5 out of 5

Friday, July 31, 2026

Weather Forecast

Patchy rain nearby
74.3°F
61.8°F
68.6°F
81%
0.06 in
60%
0%
7.6 mph
6.4


Air Quality

AQI: 1 - Good
PM2.5: 3.74 μg/m3
PM10: 4.12 μg/m3
Carbon Monoxide: 132.54 μg/m3
Nitrogen Dioxide: 3.47 μg/m3
Sulphur Dioxide: 0.59 μg/m3
Ozone: 86.08 μg/m3

Astronomical

Sunrise: 5:42 AM
Sun Transit: 12:54 AM
Sunset: 8:06 PM
Daylight: 14 hrs 24 mins
Moonrise: 9:13 PM
Moon Transit: 2:09 AM
Moonset: 7:36 AM
Moon Phase: Full
Moon Illumination: 92.0%

Best Times for Fishing or Hunting

Major Periods

1:39 AM - 4:09 AM
4:28 PM - 6:58 PM

Minor Periods

8:43 PM - 10:13 PM
7:06 AM - 8:36 AM

Action Rating: 3 out of 5

Saturday, August 1, 2026

Weather Forecast

Sunny
77.3°F
67.3°F
71.9°F
84%
0.01 in
36%
0%
11.4 mph
8.7


Air Quality

AQI: 1 - Good
PM2.5: 15.15 μg/m3
PM10: 19.15 μg/m3
Carbon Monoxide: 156.63 μg/m3
Nitrogen Dioxide: 4.32 μg/m3
Sulphur Dioxide: 1.13 μg/m3
Ozone: 118.33 μg/m3

Astronomical

Sunrise: 5:43 AM
Sun Transit: 12:54 AM
Sunset: 8:05 PM
Daylight: 14 hrs 22 mins
Moonrise: 9:34 PM
Moon Transit: 2:52 AM
Moonset: 8:42 AM
Moon Phase: Waning Gibbous
Moon Illumination: 84.9%

Best Times for Fishing or Hunting

Major Periods

2:22 AM - 4:52 AM
5:11 PM - 7:41 PM

Minor Periods

9:04 PM - 10:34 PM
8:12 AM - 9:42 AM

Action Rating: 3 out of 5

Sunday, August 2, 2026

Weather Forecast

Partly Cloudy
76.7°F
68.8°F
72.3°F
88%
0 in
22%
0%
12.8 mph
6


Air Quality

AQI: 1 - Good
PM2.5: 9.33 μg/m3
PM10: 13.77 μg/m3
Carbon Monoxide: 123.85 μg/m3
Nitrogen Dioxide: 1.66 μg/m3
Sulphur Dioxide: 0.58 μg/m3
Ozone: 80.17 μg/m3

Astronomical

Sunrise: 5:44 AM
Sun Transit: 12:54 AM
Sunset: 8:04 PM
Daylight: 14 hrs 20 mins
Moonrise: 9:55 PM
Moon Transit: 3:35 AM
Moonset: 9:48 AM
Moon Phase: Waning Gibbous
Moon Illumination: 75.9%

Best Times for Fishing or Hunting

Major Periods

3:05 AM - 5:35 AM
5:54 PM - 8:24 PM

Minor Periods

9:25 PM - 10:55 PM
9:18 AM - 10:48 AM

Action Rating: 4 out of 5

Monday, August 3, 2026

Weather Forecast

Light rain shower
73.9°F
64.6°F
69.9°F
87%
0.76 in
84%
0%
14.1 mph
6


Air Quality

AQI: 1 - Good
PM2.5: 8.53 μg/m3
PM10: 12.56 μg/m3
Carbon Monoxide: 181.11 μg/m3
Nitrogen Dioxide: 2.63 μg/m3
Sulphur Dioxide: 0.59 μg/m3
Ozone: 74.78 μg/m3

Astronomical

Sunrise: 5:45 AM
Sun Transit: 12:54 AM
Sunset: 8:03 PM
Daylight: 14 hrs 18 mins
Moonrise: 10:17 PM
Moon Transit: 12:00 AM
Moonset: 10:55 AM
Moon Phase: Waning Gibbous
Moon Illumination: 65.6%

Best Times for Fishing or Hunting

Major Periods

12:00 AM - 12:00 AM
6:39 PM - 9:09 PM

Minor Periods

9:47 PM - 11:17 PM
10:25 AM - 11:55 AM

Action Rating: 2 out of 5

The times presented here are based upon the solunar theory, which is the idea that the movements of fish and other animals are affected by the location of the sun and moon. The major periods are believed to be the times of the greatest animal activity and occur when the moon is directly overhead or underfoot (lunar transits). The minor periods also see increased activity and occur when the moon is rising or setting. The strongest activity occurs during full or new moons, and the weakest during quarter or three quarter moons. This is indicated by the Action Rating.

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