Mystic, CT weather in December
In December, Mystic sees highs around 44°F and lows around 30°F: chilly, with frequent rain and some snow. Rain or snow falls on about 12 days. Snowfall averages about 5.2 in.
- Normal high
- 44°F
- Normal low
- 30°F
- Wet days
- 12
- 4.6 in total
- Snowfall
- 5.2 in
- snow on the ground 4 days
How December changes from start to finish
| December 1 | December 31 | |
|---|---|---|
| Normal high | 48°F | 41°F |
| Normal low | 33°F | 26°F |
| Chance of a wet day | 38% | 39% |
| Sunrise / sunset | 6:54 am / 4:19 pm | 7:13 am / 4:27 pm |
| Daylight | 9.4 h | 9.2 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical December day
- 6 am32°Fdew point 25°F
- 9 am35°Fdew point 26°F
- Noon40°Fdew point 26°F
- 3 pm41°Fdew point 26°F
- 6 pm37°Fdew point 26°F
- 9 pm35°Fdew point 26°F
NOAA hourly normals (local standard time) from Providence T F Green Airport (38 mi away); average wind 9 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°Fnot available
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph0 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow12 of 31
- Notable rainat least 0.10 in8 of 31
- Freezing nightslow 32°F or below21 of 31
- Snow on the groundsnow depth 1 in or more4 of 31
Average days per December, counted from daily records for each year 1991-2020.
Rain and snow in December
Normal precipitation is 4.6 in; a dry December brings about 3.7 in and a wet one about 5.5 in (25th and 75th percentiles). About 4 days bring half an inch or more, and about 1 an inch or more. Normal snowfall is 5.2 in, with about 1 day of an inch or more.
How December varies from year to year
- Warmest December, 1991-20202015: average high 55°F
- Coolest December1995: average high 37°F
- Wettest December2020: 7.5 in
- Driest December1998: 1.2 in
- Highest reading69°F (December 1, 2001)
- Lowest reading-1°F (December 31, 1993)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
December compared with November and January
| November | December | January | |
|---|---|---|---|
| Normal high | 53°F | 44°F | 39°F |
| Normal low | 38°F | 30°F | 24°F |
| Wet days | 10 | 12 | 11 |
| Comfortable days | 2 | – | – |
| Daylight | 9.9 h | 9.2 h | 9.6 h |
Highs change by -9°F from November and -5°F into January.
Nearby alternatives in December
- Cooler: Worcester, MA63 mi · high 38°F · 12 wet days
How Mystic ranks in December
- Normal high245th warmest of 378 cities; 1st of 5 in Connecticut
- Wet days312th driest of 378
What to pack for Mystic in December
- A warm jacket – lows near 30°F, highs near 44°F
- A rain jacket or umbrella – rain or snow on about 12 days
- Waterproof boots – about 5.2 in of snow in a typical year
- A hat and gloves – about 21 freezing nights
Heating and cooling
December has 874 heating degree days and 0 cooling degree days (base 65°F), 14% of the year's total heating and cooling demand.
Questions
How cold is Mystic in December?
The normal high is 44°F and the normal low is 30°F. From 1991 to 2020 the coldest December reading was -1°F (December 31, 1993).
Does it rain a lot in Mystic in December?
About 12 days in December have at least 0.01 in of precipitation, and the normal total is 4.6 in. The wettest December in 1991-2020 was in 2020 (7.5 in); the driest was in 1998 (1.2 in).
Does it snow in Mystic in December?
Yes. Normal snowfall in December is 5.2 in, and snow covers the ground on about 4 days.
Where the numbers come from
- Temperature, rain, snowfall and snow depth: Groton (USC00063207), 3.7 mi W of the city center, 40 ft . NOAA normals and daily records, 1991-2020.
- Frost dates: Groton New London Airport (USW00014707), 4.7 mi WSW of the city center, 10 ft . NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour: Providence T F Green Airport (USW00014765), 38 mi NE of the city center, 60 ft (52 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Groton-New London Airport (725046-14707), 4.7 mi WSW of the city center, 8 ft . Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).