Data / Heating degree days / Connecticut

Heating degree days in Connecticut

Heating degree days in Connecticut was 5,765 degree days (base 65°F) in 2025, according to NOAA National Centers for Environmental Information. That is up 10.8% from 2024. That is the 19th highest of 48 states in 2025.

2025, degree days (base 65°F)5,765
Change on 2024+10.8%
Rank19th of 48US states ranked
Series high7,6051904
Series low5,0282012

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Heating degree days in Connecticut, 1895 to 2025

5,0006,0007,0008,000189519141933195219711990200920251895: 6,840 degree days (base 65°F)1896: 6,803 degree days (base 65°F)1897: 6,552 degree days (base 65°F)1898: 6,396 degree days (base 65°F)1899: 6,683 degree days (base 65°F)1900: 6,366 degree days (base 65°F)1901: 6,994 degree days (base 65°F)1902: 6,513 degree days (base 65°F)1903: 6,609 degree days (base 65°F)1904: 7,605 degree days (base 65°F)1905: 6,932 degree days (base 65°F)1906: 6,566 degree days (base 65°F)1907: 7,139 degree days (base 65°F)1908: 6,376 degree days (base 65°F)1909: 6,543 degree days (base 65°F)1910: 6,506 degree days (base 65°F)1911: 6,549 degree days (base 65°F)1912: 6,815 degree days (base 65°F)1913: 5,909 degree days (base 65°F)1914: 6,854 degree days (base 65°F)1915: 6,352 degree days (base 65°F)1916: 6,922 degree days (base 65°F)1917: 7,593 degree days (base 65°F)1918: 6,746 degree days (base 65°F)1919: 6,361 degree days (base 65°F)1920: 6,873 degree days (base 65°F)1921: 5,982 degree days (base 65°F)1922: 6,423 degree days (base 65°F)1923: 6,743 degree days (base 65°F)1924: 6,891 degree days (base 65°F)1925: 6,453 degree days (base 65°F)1926: 7,147 degree days (base 65°F)1927: 6,255 degree days (base 65°F)1928: 6,477 degree days (base 65°F)1929: 6,440 degree days (base 65°F)1930: 6,253 degree days (base 65°F)1931: 5,906 degree days (base 65°F)1932: 6,053 degree days (base 65°F)1933: 6,303 degree days (base 65°F)1934: 6,718 degree days (base 65°F)1935: 6,661 degree days (base 65°F)1936: 6,492 degree days (base 65°F)1937: 6,244 degree days (base 65°F)1938: 6,130 degree days (base 65°F)1939: 6,561 degree days (base 65°F)1940: 7,096 degree days (base 65°F)1941: 6,202 degree days (base 65°F)1942: 6,297 degree days (base 65°F)1943: 6,758 degree days (base 65°F)1944: 6,488 degree days (base 65°F)1945: 6,315 degree days (base 65°F)1946: 5,966 degree days (base 65°F)1947: 6,467 degree days (base 65°F)1948: 6,518 degree days (base 65°F)1949: 5,717 degree days (base 65°F)1950: 6,361 degree days (base 65°F)1951: 6,006 degree days (base 65°F)1952: 6,045 degree days (base 65°F)1953: 5,526 degree days (base 65°F)1954: 6,075 degree days (base 65°F)1955: 6,362 degree days (base 65°F)1956: 6,458 degree days (base 65°F)1957: 5,984 degree days (base 65°F)1958: 6,808 degree days (base 65°F)1959: 6,088 degree days (base 65°F)1960: 6,374 degree days (base 65°F)1961: 6,398 degree days (base 65°F)1962: 6,718 degree days (base 65°F)1963: 6,592 degree days (base 65°F)1964: 6,302 degree days (base 65°F)1965: 6,505 degree days (base 65°F)1966: 6,460 degree days (base 65°F)1967: 6,709 degree days (base 65°F)1968: 6,499 degree days (base 65°F)1969: 6,432 degree days (base 65°F)1970: 6,558 degree days (base 65°F)1971: 6,346 degree days (base 65°F)1972: 6,608 degree days (base 65°F)1973: 5,803 degree days (base 65°F)1974: 6,276 degree days (base 65°F)1975: 6,029 degree days (base 65°F)1976: 6,548 degree days (base 65°F)1977: 6,327 degree days (base 65°F)1978: 6,790 degree days (base 65°F)1979: 6,091 degree days (base 65°F)1980: 6,496 degree days (base 65°F)1981: 6,334 degree days (base 65°F)1982: 6,332 degree days (base 65°F)1983: 6,026 degree days (base 65°F)1984: 6,118 degree days (base 65°F)1985: 6,115 degree days (base 65°F)1986: 6,124 degree days (base 65°F)1987: 6,119 degree days (base 65°F)1988: 6,429 degree days (base 65°F)1989: 6,445 degree days (base 65°F)1990: 5,370 degree days (base 65°F)1991: 5,477 degree days (base 65°F)1992: 6,378 degree days (base 65°F)1993: 6,270 degree days (base 65°F)1994: 6,241 degree days (base 65°F)1995: 6,145 degree days (base 65°F)1996: 6,270 degree days (base 65°F)1997: 6,140 degree days (base 65°F)1998: 5,236 degree days (base 65°F)1999: 5,614 degree days (base 65°F)2000: 6,108 degree days (base 65°F)2001: 5,672 degree days (base 65°F)2002: 5,697 degree days (base 65°F)2003: 6,458 degree days (base 65°F)2004: 6,148 degree days (base 65°F)2005: 6,178 degree days (base 65°F)2006: 5,416 degree days (base 65°F)2007: 5,945 degree days (base 65°F)2008: 5,908 degree days (base 65°F)2009: 6,103 degree days (base 65°F)2010: 5,524 degree days (base 65°F)2011: 5,605 degree days (base 65°F)2012: 5,028 degree days (base 65°F)2013: 5,930 degree days (base 65°F)2014: 6,205 degree days (base 65°F)2015: 5,938 degree days (base 65°F)2016: 5,364 degree days (base 65°F)2017: 5,440 degree days (base 65°F)2018: 5,739 degree days (base 65°F)2019: 5,937 degree days (base 65°F)2020: 5,344 degree days (base 65°F)2021: 5,410 degree days (base 65°F)2022: 5,627 degree days (base 65°F)2023: 5,057 degree days (base 65°F)2024: 5,202 degree days (base 65°F)2025: 5,765 degree days (base 65°F)
degree days (base 65°F). Source: NOAA NCEI, NOAA Climate at a Glance, January to December heating degree days (base 65°F), contiguous US and statewide. Retrieved 2026-10-12, published 2026-10-06.
All 131 values
Perioddegree days (base 65°F)
20255,765
20245,202
20235,057
20225,627
20215,410
20205,344
20195,937
20185,739
20175,440
20165,364
20155,938
20146,205
20135,930
20125,028
20115,605
20105,524
20096,103
20085,908
20075,945
20065,416
20056,178
20046,148
20036,458
20025,697
20015,672
20006,108
19995,614
19985,236
19976,140
19966,270
19956,145
19946,241
19936,270
19926,378
19915,477
19905,370
19896,445
19886,429
19876,119
19866,124
19856,115
19846,118
19836,026
19826,332
19816,334
19806,496
19796,091
19786,790
19776,327
19766,548
19756,029
19746,276
19735,803
19726,608
19716,346
19706,558
19696,432
19686,499
19676,709
19666,460
19656,505
19646,302
19636,592
19626,718
19616,398
19606,374
19596,088
19586,808
19575,984
19566,458
19556,362
19546,075
19535,526
19526,045
19516,006
19506,361
19495,717
19486,518
19476,467
19465,966
19456,315
19446,488
19436,758
19426,297
19416,202
19407,096
19396,561
19386,130
19376,244
19366,492
19356,661
19346,718
19336,303
19326,053
19315,906
19306,253
19296,440
19286,477
19276,255
19267,147
19256,453
19246,891
19236,743
19226,423
19215,982
19206,873
19196,361
19186,746
19177,593
19166,922
19156,352
19146,854
19135,909
19126,815
19116,549
19106,506
19096,543
19086,376
19077,139
19066,566
19056,932
19047,605
19036,609
19026,513
19016,994
19006,366
18996,683
18986,396
18976,552
18966,803
18956,840

Compared with United States

Place2025
Connecticut5,765
United States4,062

Rankings

Definition

Sum over January to December of the degrees by which the daily mean temperature falls below 65°F, a measure of heating 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 heating 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/hdd/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 heating degree days (base 65°F), contiguous US and statewide (Heating 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/hdd/12/12/1895-2025/data.json

MLA 9

NOAA Climate at a Glance, January to December heating degree days (base 65°F), contiguous US and statewide, Heating 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/hdd/12/12/1895-2025/data.json. Invokely, https://invokely.ai/en/heating-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 heating degree days (base 65°F), contiguous US and statewide. Heating 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/hdd/12/12/1895-2025/data.json. Also distributed by Invokely, https://invokely.ai/en/heating-degree-days/connecticut.

Harvard

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

BibTeX
@misc{noaa_heating_degree_days_connecticut_2025,
  author = {{NOAA National Centers for Environmental Information}},
  title = {{NOAA Climate at a Glance, January to December heating degree days (base 65°F), contiguous US and statewide: Heating 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/hdd/12/12/1895-2025/data.json},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/en/heating-degree-days/connecticut. Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December heating 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/hdd/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 heating degree days (base 65°F), contiguous US and statewide: Heating 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/hdd/12/12/1895-2025/data.json
L2  - https://invokely.ai/en/heating-degree-days/connecticut
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/heating-degree-days/connecticut.
N1  - Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December heating 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/hdd/12/12/1895-2025/data.json. Retrieved 2026-10-12.
ER  -
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Questions

What is the heating degree days in Connecticut?

Heating degree days in Connecticut was 5,765 degree days (base 65°F) in 2025, according to NOAA National Centers for Environmental Information. That is up 10.8% from 2024. That is the 19th highest of 48 states in 2025.

Where does this figure come from?

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

What was the highest heating degree days in Connecticut?

7,605 degree days (base 65°F) in 1904, the highest value since 1895 in this series.

Heating degree days elsewhere in United States

Related statistics for Connecticut

All statistics for Connecticut | Connecticut in figures