Groton weather in January: Groton, Connecticut: normal highs, lows, rain and records for January
Groton in January has a normal high of 38°F and a normal low of 23°F, a daily mean of 31°F, falling from 40°F on the 1st to 38°F by the 31st. Measurable precipitation falls on 9 days in a normal January, 2.68 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 3°C and low of −5°C, 68 mm of precipitation in January.
- NOAA stationGroton New London Airport
- Station IDUSW00014707
- Location41.33°N 72.05°W
- Elevation10 ft (3 m)
- Population10,160
- Jan 38° 23°
- Feb 40° 25°
- Mar 47° 31°
- Apr 56° 39°
- May 65° 49°
- Jun 74° 58°
- Jul 80° 65°
- Aug 79° 64°
- Sep 74° 57°
- Oct 63° 46°
- Nov 53° 37°
- Dec 44° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Groton in January?
The normal high is 38°F and the normal low 23°F, for a daily mean of 30.8°F. January is 5.7°F cooler than December and 1.6°F cooler than February. January is the 12th warmest month of the year in Groton and the 11th wettest. Across the month the normal high falls 2°F, from 40°F on January 1 to 38°F on January 31. From one year to the next January's mean temperature typically moves about 4.0°F either way (NOAA's standard deviation), so roughly two Januarys in three average between 27°F and 35°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 32%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| January 1 | 40°F | 25°F | 32% | 18% |
| January 8 | 39°F | 24°F | 30% | 17% |
| January 15 | 38°F | 23°F | 29% | 16% |
| January 22 | 38°F | 23°F | 27% | 15% |
| January 31 | 38°F | 23°F | 26% | 15% |
Every day of January: normal high, low and chance of precipitation (warmest afternoon January 1, coldest night January 21)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| January 1 | 40°F | 25°F | 32% | 18% | 9 h 10 min |
| January 2 | 40°F | 25°F | 31% | 18% | 9 h 20 min |
| January 3 | 40°F | 25°F | 31% | 18% | 9 h 20 min |
| January 4 | 39°F | 25°F | 31% | 18% | 9 h 20 min |
| January 5 | 39°F | 24°F | 31% | 18% | 9 h 20 min |
| January 6 | 39°F | 24°F | 31% | 18% | 9 h 20 min |
| January 7 | 39°F | 24°F | 31% | 17% | 9 h 20 min |
| January 8 | 39°F | 24°F | 30% | 17% | 9 h 20 min |
| January 9 | 39°F | 24°F | 30% | 17% | 9 h 20 min |
| January 10 | 39°F | 24°F | 30% | 17% | 9 h 20 min |
| January 11 | 38°F | 24°F | 30% | 17% | 9 h 20 min |
| January 12 | 38°F | 23°F | 30% | 17% | 9 h 30 min |
| January 13 | 38°F | 23°F | 29% | 17% | 9 h 30 min |
| January 14 | 38°F | 23°F | 29% | 16% | 9 h 30 min |
| January 15 | 38°F | 23°F | 29% | 16% | 9 h 30 min |
| January 16 | 38°F | 23°F | 29% | 16% | 9 h 30 min |
| January 17 | 38°F | 23°F | 29% | 16% | 9 h 30 min |
| January 18 | 38°F | 23°F | 28% | 16% | 9 h 30 min |
| January 19 | 38°F | 23°F | 28% | 16% | 9 h 40 min |
| January 20 | 38°F | 23°F | 28% | 16% | 9 h 40 min |
| January 21 | 38°F | 23°F | 27% | 15% | 9 h 40 min |
| January 22 | 38°F | 23°F | 27% | 15% | 9 h 40 min |
| January 23 | 38°F | 23°F | 27% | 15% | 9 h 40 min |
| January 24 | 38°F | 23°F | 27% | 15% | 9 h 50 min |
| January 25 | 38°F | 23°F | 26% | 15% | 9 h 50 min |
| January 26 | 38°F | 23°F | 26% | 15% | 9 h 50 min |
| January 27 | 38°F | 23°F | 26% | 15% | 9 h 50 min |
| January 28 | 38°F | 23°F | 26% | 15% | 9 h 50 min |
| January 29 | 38°F | 23°F | 26% | 15% | 10 h |
| January 30 | 38°F | 23°F | 26% | 15% | 10 h |
| January 31 | 38°F | 23°F | 26% | 15% | 10 h |
- Normal high
- 38°FJanuary average
- Normal low
- 23°FJanuary average
- Precipitation
- 2.68 inmonth total
- Days with precipitation
- 90.01 inch or more
- Nights at 32°F or colder
- 25
- Daylight
- 9 h 10 min to 10 hJanuary 1 to January 31
- Sunshine
- 70%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014707; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Groton in January?
On a given January day the chance of 0.01 inch or more is 29% on average, highest around January 1 (32%). In all, 2.68 in falls on 9 days of a normal January.
In a normal January in Groton, 25 nights fall to freezing and 8 days stay below freezing all day.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014707.
What are the records for January in Groton?
The warmest January temperature on this station's record (since 1999) is 66°F, on January 12, 2020; the coldest is −7°F, on January 16, 2009. The wettest January brought 6.46 in (2024).
The January mean against the 1991-2020 normal of 30.8°F: 2021 31.9°F (+1.1), 2022 27.9°F (−2.9), 2023 40.9°F (+10.1), 2024 34.5°F (+3.7), 2025 29.0°F (−1.8), 2026 28.2°F (−2.6). 3 of 6 ran warmer than normal.
| January | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 31.9°F | +1.1°F | 2.74 in |
| 2022 | 27.9°F | −2.9°F | 2.01 in |
| 2023 | 40.9°F | +10.1°F | 4.98 in |
| 2024 | 34.5°F | +3.7°F | 6.46 in |
| 2025 | 29.0°F | −1.8°F | 1.16 in |
| 2026 | 28.2°F | −2.6°F | 0.68 in |
Source: records: ACIS, station USW00014707; recent months: ACIS, station USW00014707. Records and recent months use complete months only.
How does January in Groton compare across Connecticut?
Across the 13 places PlainClimate covers in Connecticut, January normal highs run from 30°F in Norfolk to 38°F in Bridgeport; Groton's is 38°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.