Climateby Month

Mystic, CT climate by month

NOAA 1991-2020 normals · 8 ft elevation

Mystic has warm and often humid summers and cold and snowy winters. Highs peak at 81°F in July and fall to 39°F in January. Wet days are spread through the year, from about 9 to 12 a month. Normal snowfall is about 25 in a year. By our comfort score the best month is November.

Warmest month
81°F
July normal high
Coldest month
24°F
January normal low
Wet days a year
127
48.9 in of precipitation
Snow a year
24.5 in
normal snowfall

How warm is Mystic?

Normal highs range from 39°F in January to 81°F in July.

20°40°60°80°100° January: normal high 39°F (4°C), low 24°F (-4°C) 39° 24° February: normal high 41°F (5°C), low 25°F (-4°C) March: normal high 47°F (8°C), low 32°F (0°C) April: normal high 57°F (14°C), low 41°F (5°C) May: normal high 66°F (19°C), low 50°F (10°C) June: normal high 75°F (24°C), low 59°F (15°C) July: normal high 81°F (27°C), low 66°F (19°C) 81° 66° August: normal high 80°F (27°C), low 65°F (18°C) September: normal high 74°F (23°C), low 58°F (14°C) October: normal high 63°F (17°C), low 47°F (8°C) November: normal high 53°F (12°C), low 38°F (3°C) December: normal high 44°F (7°C), low 30°F (-1°C) JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is Mystic?

December has the most wet days (about 12); the year brings about 49 in of precipitation.

January: 11 wet days February: 10 wet days March: 12 wet days April: 12 wet days May: 12 wet days June: 10 wet days July: 10 wet days August: 9 wet days 9 September: 10 wet days October: 10 wet days November: 10 wet days December: 12 wet days 12 JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How much does it snow?

Normal snowfall is 24.5 in a year, most of it in February.

January: 5.8 in of snow February: 8.3 in of snow 8.3 March: 3.9 in of snow April: 0.8 in of snow May: 0.0 in of snow 0.0 June: 0.0 in of snow July: 0.0 in of snow August: 0.0 in of snow September: 0.0 in of snow October: 0.0 in of snow November: 0.5 in of snow December: 5.2 in of snow JFMAMJJASOND

How humid is Mystic?

Muggy days peak in July, at about 18 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 5 muggy days July: 18 muggy days 18 August: 14 muggy days September: 7 muggy days October: 1 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Groton-New London Airport, 4.7 mi WSW of the city center.

How much daylight?

Daylight ranges from about 9.2 hours in December to 15.1 hours in June.

January: 9.6 hours of daylight February: 10.6 hours of daylight March: 12.0 hours of daylight April: 13.3 hours of daylight May: 14.5 hours of daylight June: 15.1 hours of daylight 15.1 July: 14.8 hours of daylight August: 13.8 hours of daylight September: 12.5 hours of daylight October: 11.1 hours of daylight November: 9.9 hours of daylight December: 9.2 hours of daylight 9.2 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Mystic, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 39°F24°F 3.9 in11 5.8 in 0 9.6 h
February 41°F25°F 3.4 in10 8.3 in 0 10.6 h
March 47°F32°F 4.9 in12 3.9 in 0 12.0 h
April 57°F41°F 4.4 in12 0.8 in 0 13.3 h
May 66°F50°F 3.7 in12 0.0 in 0 14.5 h
June 75°F59°F 3.9 in10 0.0 in 5 15.1 h
July 81°F66°F 3.4 in10 0.0 in 18 14.8 h
August 80°F65°F 4.2 in9 0.0 in 14 13.8 h
September 74°F58°F 4.3 in10 0.0 in 7 12.5 h
October 63°F47°F 4.4 in10 0.0 in 1 11.1 h
November 53°F38°F 3.8 in10 0.5 in 0 9.9 h
December 44°F30°F 4.6 in12 5.2 in 0 9.2 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit Mystic

By our comfort score, the best month is November.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Feb 340713
Nov 44262

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in Mystic

The last spring frost typically comes around Apr 16, and the first fall frost around Oct 28, leaving 194 frost-free days in a typical year.

Frost and freeze dates for Mystic
Typical date1 year in 10
Last spring frost (32°F)Apr 16after Apr 30
First fall frost (32°F)Oct 28before Oct 13
Last hard freeze (28°F)Apr 3after Apr 17
First hard freeze (28°F)Nov 9before Oct 25
Frost-free season194 daysunder 175 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Groton New London Airport (USW00014707), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Connecticut.

Hottest and coldest readings, 1991-2020

The highest reading was 101°F (July 21, 1991); the lowest was -9°F (February 5, 1996).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near Mystic

Similar climates elsewhere

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).

Distances from the city center (USGS). Methodology · Report an error