Cooling degree days in Connecticut

Cooling degree days in Connecticut was 695 degree days (base 65°F) in 2025, according to NOAA National Centers for Environmental Information. That is down 2.8% from 2024. That is the 32nd highest of 48 states in 2025.

2025, degree days (base 65°F)695

Change on 2024-2.8%

Rank32nd of 48US states ranked

Series high8222018

Series low2331903

Next release: Wednesday, 6 October 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

Cooling degree days in Connecticut, 1895 to 2025

degree days (base 65°F). Source: NOAA NCEI, NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide. Retrieved 2026-10-12, published 2026-10-06.

All 131 values

Period	degree days (base 65°F)
2025	695
2024	715
2023	631
2022	774
2021	706
2020	772
2019	666
2018	822
2017	592
2016	796
2015	715
2014	529
2013	644
2012	702
2011	712
2010	786
2009	444
2008	571
2007	564
2006	599
2005	751
2004	477
2003	557
2002	619
2001	570
2000	360
1999	707
1998	582
1997	441
1996	466
1995	594
1994	631
1993	594
1992	322
1991	611
1990	527
1989	477
1988	602
1987	489
1986	371
1985	413
1984	500
1983	593
1982	371
1981	502
1980	567
1979	477
1978	402
1977	466
1976	442
1975	483
1974	435
1973	593
1972	422
1971	493
1970	505
1969	468
1968	463
1967	445
1966	486
1965	392
1964	351
1963	367
1962	293
1961	538
1960	394
1959	569
1958	357
1957	448
1956	355
1955	646
1954	338
1953	470
1952	581
1951	418
1950	344
1949	676
1948	472
1947	473
1946	324
1945	446
1944	621
1943	567
1942	439
1941	424
1940	324
1939	510
1938	482
1937	544
1936	460
1935	463
1934	509
1933	477
1932	417
1931	555
1930	512
1929	383
1928	450
1927	259
1926	345
1925	440
1924	338
1923	343
1922	407
1921	487
1920	363
1919	379
1918	376
1917	453
1916	413
1915	327
1914	320
1913	405
1912	342
1911	476
1910	387
1909	322
1908	504
1907	320
1906	472
1905	353
1904	313
1903	233
1902	244
1901	510
1900	560
1899	390
1898	497
1897	315
1896	406
1895	393

Compared with United States

Place	2025
Connecticut	695
United States	1,502

Rankings

US states by cooling degree days 48 places

Definition

Sum over January to December of the degrees by which the daily mean temperature exceeds 65°F, a measure of cooling demand. NOAA estimates monthly values from nClimDiv temperatures and weights areas by population (2010 Census).

NOAA publishes these for operational monitoring; they can differ from official degree day publications.

How to cite

NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

NOAA National Centers for Environmental Information. (2026). NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide (Cooling degree days, Connecticut, 1895 to 2025) [Data set]. Retrieved October 12, 2026, from https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json

MLA 9

NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide, Cooling degree days, Connecticut, 1895 to 2025. NOAA National Centers for Environmental Information, 6 Oct. 2026, https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json. Invokely, https://invokely.ai/en/cooling-degree-days/connecticut. Accessed 12 Oct. 2026.

Chicago (author-date)

NOAA National Centers for Environmental Information. 2026. NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide. Cooling degree days, Connecticut, 1895 to 2025. Dataset. Accessed October 12, 2026. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json. Also distributed by Invokely, https://invokely.ai/en/cooling-degree-days/connecticut.

Harvard

NOAA National Centers for Environmental Information (2026) NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide, Cooling degree days, Connecticut, 1895 to 2025 [Dataset]. Available at: https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json, via Invokely: https://invokely.ai/en/cooling-degree-days/connecticut (Accessed: 12 October 2026).

BibTeX

@misc{noaa_cooling_degree_days_connecticut_2025,
  author = {{NOAA National Centers for Environmental Information}},
  title = {{NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide: Cooling degree days, Connecticut, 1895 to 2025}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/en/cooling-degree-days/connecticut. Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json. Retrieved 2026-10-12.},
}

RIS

TY  - DATA
AU  - NOAA National Centers for Environmental Information
TI  - NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide: Cooling degree days, Connecticut, 1895 to 2025
PY  - 2026
DA  - 2026/10/06
PB  - NOAA National Centers for Environmental Information
DB  - Invokely
UR  - https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json
L2  - https://invokely.ai/en/cooling-degree-days/connecticut
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/cooling-degree-days/connecticut.
N1  - Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/statewide/time-series/6/cdd/12/12/1895-2025/data.json. Retrieved 2026-10-12.
ER  -

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Questions

What is the cooling degree days in Connecticut?

Where does this figure come from?

NOAA National Centers for Environmental Information. NOAA Climate at a Glance, January to December cooling degree days (base 65°F), contiguous US and statewide. Retrieved by Invokely on 2026-10-12.

What was the highest cooling degree days in Connecticut?

822 degree days (base 65°F) in 2018, the highest value since 1895 in this series.

Cooling degree days elsewhere in United States

Related statistics for Connecticut

All statistics for Connecticut | Connecticut in figures