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Old Mystic CDP, Connecticut

Official LSAD Designation: Old Mystic CDP • Census GEOID: 0957180 • Southeastern Connecticut Planning Region

Climate Normals & Weather Observations

30-year climate normals (1991–2020) and weather observations for Old Mystic CDP.

Reference Weather Station: GROTON, CT US (ID: USC00063207) • Located 3.5 miles from community center • Elevation: 12.2 m
Month Average High (°F) Average Low (°F) Mean Temp (°F) Precipitation (in)
January 38.8° 23.8° 31.3° 3.91"
February 40.8° 24.9° 32.9° 3.42"
March 47.3° 31.6° 39.5° 4.92"
April 56.9° 40.9° 48.9° 4.40"
May 66.4° 49.9° 58.1° 3.67"
June 75.2° 59.3° 67.3° 3.93"
July 80.8° 65.9° 73.4° 3.42"
August 79.8° 65.1° 72.5° 4.19"
September 73.6° 58.0° 65.8° 4.29"
October 63.3° 47.1° 55.2° 4.42"
November 53.2° 37.9° 45.5° 3.75"
December 44.1° 29.5° 36.8° 4.59"

Annual Temperature History

2010–2025, completed calendar years only.

NOAA station GROTON, CT US (ID: USC00063207) • 3.5 miles from community center .

This is the same reference station used for monthly normals.

Annual mean Annual mean of daily highs Annual mean of daily lows
Annual temperature history at GROTON, CT US Year is the horizontal axis. Annual mean temperature in degrees Fahrenheit is the vertical axis. Dots show recorded years; lines connect consecutive available years only. Missing years are gaps, with no interpolation. Optional dashed lines show annual mean of daily highs and lows. Exact values appear in the data table below. 43.0 48.3 53.5 58.8 64.0 2010 2014 2018 2021 2025 Year Annual mean temperature (°F) 2011: Annual mean 53.2°F 2024: Annual mean 53.9°F 2011: Annual mean of daily highs 60.9°F 2024: Annual mean of daily highs 61.6°F 2011: Annual mean of daily lows 45.4°F 2024: Annual mean of daily lows 46.2°F

Source: NOAA NCEI Global Summary of the Year.

Annual temperature data table (°F)
Annual station temperatures, 2010–2025. Unavailable means no reported value.
Year Annual mean (°F) Annual mean of daily highs (°F) Annual mean of daily lows (°F)
2010 Unavailable Unavailable Unavailable
2011 53.2 60.9 45.4
2012 Unavailable Unavailable Unavailable
2013 Unavailable Unavailable Unavailable
2014 Unavailable Unavailable Unavailable
2015 Unavailable Unavailable Unavailable
2016 Unavailable Unavailable Unavailable
2017 Unavailable Unavailable Unavailable
2018 Unavailable Unavailable Unavailable
2019 Unavailable Unavailable Unavailable
2020 Unavailable Unavailable Unavailable
2021 Unavailable Unavailable Unavailable
2022 Unavailable Unavailable Unavailable
2023 Unavailable Unavailable Unavailable
2024 53.9 61.6 46.2
2025 Unavailable Unavailable Unavailable
Source: NOAA NCEI 1991–2020 U.S. Climate Normals, National Weather Service.