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Built 2026-10-19 (19 October 2026)

Nights at or above 20 C (68 F) in Boston

Boston has had nights with a minimum temperature at or above 20 C (68 F) in 91 years, most in 1983 with 49. Days per year, season span, streaks and every date.

Key Facts for Boston

  • Boston has had nights with a minimum temperature at or above 20 C (68 F) in 91 years, 2,211 days in all.
  • The most in one year was 49 days in 1983.
  • In 2026, the latest year on file, there were 33 such days.
  • The earliest first date in a year was 4 May 2001.
  • The latest last date in a year was 10 October 2018.
  • The longest run inside a single year was 20 days in 2020.
  • 1 year with under 90 percent of days observed is left out of these rankings.

Days per Year

91 years, 2,211 days
Nights at or above 20 C (68 F) per year in Boston Days per year in Boston with a minimum temperature at or above 20 C (68 F). The line is the decade average. The most was 49 in 1983. Grey bars are years with under 90 percent of days observed, left out of rankings. 02040601936: 71937: 271938: 211939: 181940: 101941: 161942: 151943: 211944: 261945: 211946: 111947: 281948: 201949: 331950: 91951: 161952: 291953: 211954: 101955: 381956: 161957: 241958: 131959: 331960: 211961: 261962: 41963: 171964: 101965: 131966: 161967: 221968: 191969: 261970: 191971: 201972: 131973: 341974: 151975: 301976: 331977: 231978: 171979: 311980: 341981: 251982: 201983: 491984: 341985: 181986: 171987: 141988: 301989: 181990: 261991: 271992: 91993: 221994: 281995: 281996: 191997: 201998: 231999: 332000: 132001: 242002: 332003: 282004: 202005: 312006: 282007: 242008: 212009: 232010: 362011: 372012: 342013: 322014: 182015: 302016: 422017: 272018: 462019: 412020: 382021: 472022: 322023: 372024: 252025: 252026: 331936194619561966197619861996200620162026
Days per year in Boston with a minimum temperature at or above 20 C (68 F). The line is the decade average. The most was 49 in 1983. Grey bars are years with under 90 percent of days observed, left out of rankings.
Nights at or above 20 C (68 F) per year in Boston
YearDaysDecade average
1936718.3
19372718.3
19382118.3
19391818.3
19401020.1
19411620.1
19421520.1
19432120.1
19442620.1
19452120.1
19461120.1
19472820.1
19482020.1
19493320.1
1950920.9
19511620.9
19522920.9
19532120.9
19541020.9
19553820.9
19561620.9
19572420.9
19581320.9
19593320.9
19602117.4
19612617.4
1962417.4
19631717.4
19641017.4
19651317.4
19661617.4
19672217.4
19681917.4
19692617.4
19701923.5
19712023.5
19721323.5
19733423.5
19741523.5
19753023.5
19763323.5
19772323.5
19781723.5
19793123.5
19803425.9
19812525.9
19822025.9
19834925.9
19843425.9
19851825.9
19861725.9
19871425.9
19883025.9
19891825.9
19902623.5
19912723.5
1992923.5
19932223.5
19942823.5
19952823.5
19961923.5
19972023.5
19982323.5
19993323.5
20001324.5
20012424.5
20023324.5
20032824.5
20042024.5
20053124.5
20062824.5
20072424.5
20082124.5
20092324.5
20103634.3
20113734.3
20123434.3
20133234.3
20141834.3
20153034.3
20164234.3
20172734.3
20184634.3
20194134.3
20203833.9
20214733.9
20223233.9
20233733.9
20242533.9
20252533.9
20263333.9

Season Span

earliest 4 May, latest 10 October
First to last qualifying date each year in Boston For each year, a bar from the first to the last day in Boston meeting 20 C (68 F). Long bars mean a long season. 1936: 8 July 1936 to 8 September 19361937: 1 June 1937 to 3 September 19371938: 23 June 1938 to 17 August 19381939: 21 June 1939 to 16 September 19391940: 10 July 1940 to 31 August 19401941: 20 June 1941 to 17 September 19411942: 12 June 1942 to 23 August 19421943: 3 June 1943 to 7 September 19431944: 28 May 1944 to 2 September 19441945: 12 June 1945 to 25 September 19451946: 26 June 1946 to 10 August 19461947: 28 June 1947 to 15 September 19471948: 25 June 1948 to 29 August 19481949: 12 June 1949 to 29 August 19491950: 8 June 1950 to 29 August 19501951: 8 July 1951 to 14 September 19511952: 26 June 1952 to 2 September 19521953: 6 June 1953 to 6 September 19531954: 22 June 1954 to 1 October 19541955: 19 June 1955 to 1 September 19551956: 14 June 1956 to 19 August 19561957: 15 June 1957 to 22 September 19571958: 1 July 1958 to 31 August 19581959: 28 May 1959 to 24 September 19591960: 25 June 1960 to 9 September 19601961: 13 June 1961 to 12 September 19611962: 11 June 1962 to 7 August 19621963: 25 June 1963 to 22 August 19631964: 24 May 1964 to 31 August 19641965: 29 June 1965 to 21 September 19651966: 28 June 1966 to 30 August 19661967: 16 June 1967 to 22 August 19671968: 30 June 1968 to 25 August 19681969: 14 June 1969 to 1 September 19691970: 5 July 1970 to 23 September 19701971: 26 June 1971 to 9 September 19711972: 3 July 1972 to 28 August 19721973: 9 June 1973 to 3 September 19731974: 3 July 1974 to 13 September 19741975: 18 June 1975 to 27 August 19751976: 8 June 1976 to 28 August 19761977: 25 May 1977 to 3 September 19771978: 28 June 1978 to 30 August 19781979: 10 May 1979 to 7 September 19791980: 25 June 1980 to 22 September 19801981: 16 June 1981 to 13 August 19811982: 26 June 1982 to 3 September 19821983: 12 June 1983 to 21 September 19831984: 8 June 1984 to 11 September 19841985: 6 July 1985 to 4 September 19851986: 16 June 1986 to 30 September 19861987: 31 May 1987 to 18 August 19871988: 13 June 1988 to 28 August 19881989: 27 June 1989 to 22 September 19891990: 4 July 1990 to 29 August 19901991: 25 May 1991 to 17 September 19911992: 10 July 1992 to 18 September 19921993: 27 June 1993 to 15 September 19931994: 14 June 1994 to 17 September 19941995: 18 June 1995 to 1 September 19951996: 11 June 1996 to 6 September 19961997: 11 June 1997 to 17 August 19971998: 24 June 1998 to 26 August 19981999: 7 June 1999 to 10 September 19992000: 17 June 2000 to 9 September 20002001: 4 May 2001 to 31 August 20012002: 24 June 2002 to 22 September 20022003: 26 June 2003 to 20 September 20032004: 9 June 2004 to 29 August 20042005: 11 June 2005 to 1 September 20052006: 19 June 2006 to 15 August 20062007: 25 May 2007 to 27 September 20072008: 8 June 2008 to 6 September 20082009: 17 July 2009 to 26 August 20092010: 21 June 2010 to 3 September 20102011: 9 June 2011 to 25 September 20112012: 21 June 2012 to 7 September 20122013: 31 May 2013 to 11 September 20132014: 18 June 2014 to 6 September 20142015: 6 July 2015 to 9 September 20152016: 31 May 2016 to 21 September 20162017: 18 May 2017 to 8 October 20172018: 19 June 2018 to 10 October 20182019: 29 June 2019 to 23 September 20192020: 19 June 2020 to 10 September 20202021: 6 June 2021 to 24 September 20212022: 26 June 2022 to 11 September 20222023: 24 June 2023 to 11 September 20232024: 19 June 2024 to 1 September 20242025: 19 June 2025 to 26 September 20252026: 19 May 2026 to 10 September 202619361948196019721984199620082020JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day in Boston meeting 20 C (68 F). Long bars mean a long season.
First to last qualifying date each year in Boston
YearFirst dateLast date
19361936-07-081936-09-08
19371937-06-011937-09-03
19381938-06-231938-08-17
19391939-06-211939-09-16
19401940-07-101940-08-31
19411941-06-201941-09-17
19421942-06-121942-08-23
19431943-06-031943-09-07
19441944-05-281944-09-02
19451945-06-121945-09-25
19461946-06-261946-08-10
19471947-06-281947-09-15
19481948-06-251948-08-29
19491949-06-121949-08-29
19501950-06-081950-08-29
19511951-07-081951-09-14
19521952-06-261952-09-02
19531953-06-061953-09-06
19541954-06-221954-10-01
19551955-06-191955-09-01
19561956-06-141956-08-19
19571957-06-151957-09-22
19581958-07-011958-08-31
19591959-05-281959-09-24
19601960-06-251960-09-09
19611961-06-131961-09-12
19621962-06-111962-08-07
19631963-06-251963-08-22
19641964-05-241964-08-31
19651965-06-291965-09-21
19661966-06-281966-08-30
19671967-06-161967-08-22
19681968-06-301968-08-25
19691969-06-141969-09-01
19701970-07-051970-09-23
19711971-06-261971-09-09
19721972-07-031972-08-28
19731973-06-091973-09-03
19741974-07-031974-09-13
19751975-06-181975-08-27
19761976-06-081976-08-28
19771977-05-251977-09-03
19781978-06-281978-08-30
19791979-05-101979-09-07
19801980-06-251980-09-22
19811981-06-161981-08-13
19821982-06-261982-09-03
19831983-06-121983-09-21
19841984-06-081984-09-11
19851985-07-061985-09-04
19861986-06-161986-09-30
19871987-05-311987-08-18
19881988-06-131988-08-28
19891989-06-271989-09-22
19901990-07-041990-08-29
19911991-05-251991-09-17
19921992-07-101992-09-18
19931993-06-271993-09-15
19941994-06-141994-09-17
19951995-06-181995-09-01
19961996-06-111996-09-06
19971997-06-111997-08-17
19981998-06-241998-08-26
19991999-06-071999-09-10
20002000-06-172000-09-09
20012001-05-042001-08-31
20022002-06-242002-09-22
20032003-06-262003-09-20
20042004-06-092004-08-29
20052005-06-112005-09-01
20062006-06-192006-08-15
20072007-05-252007-09-27
20082008-06-082008-09-06
20092009-07-172009-08-26
20102010-06-212010-09-03
20112011-06-092011-09-25
20122012-06-212012-09-07
20132013-05-312013-09-11
20142014-06-182014-09-06
20152015-07-062015-09-09
20162016-05-312016-09-21
20172017-05-182017-10-08
20182018-06-192018-10-10
20192019-06-292019-09-23
20202020-06-192020-09-10
20212021-06-062021-09-24
20222022-06-262022-09-11
20232023-06-242023-09-11
20242024-06-192024-09-01
20252025-06-192025-09-26
20262026-05-192026-09-10

Every Year

Nights at or above 20 C (68 F) per year in Boston
YearDaysFirst dateLast dateLongest streak in yearCoverage
20263319 May 202610 September 20269 daysIncomplete, not ranked
20252519 June 202526 September 20254 daysComplete
20242519 June 20241 September 202410 daysComplete
20233724 June 202311 September 20239 daysComplete
20223226 June 202211 September 202211 daysComplete
2021476 June 202124 September 202110 daysComplete
20203819 June 202010 September 202020 daysComplete
20194129 June 201923 September 20199 daysComplete
20184619 June 201810 October 201819 daysComplete
20172718 May 20178 October 20177 daysComplete
20164231 May 201621 September 201613 daysComplete
2015306 July 20159 September 20158 daysComplete
20141818 June 20146 September 20144 daysComplete
20133231 May 201311 September 201310 daysComplete
20123421 June 20127 September 20129 daysComplete
2011379 June 201125 September 20117 daysComplete
20103621 June 20103 September 201010 daysComplete
20092317 July 200926 August 200911 daysComplete
2008218 June 20086 September 20084 daysComplete
20072425 May 200727 September 20075 daysComplete
20062819 June 200615 August 20065 daysComplete
20053111 June 20051 September 20057 daysComplete
2004209 June 200429 August 20046 daysComplete
20032826 June 200320 September 20035 daysComplete
20023324 June 200222 September 20029 daysComplete
2001244 May 200131 August 20015 daysComplete
20001317 June 20009 September 20004 daysComplete
1999337 June 199910 September 19997 daysComplete
19982324 June 199826 August 19985 daysComplete
19972011 June 199717 August 19973 daysComplete
19961911 June 19966 September 19966 daysComplete
19952818 June 19951 September 199514 daysComplete
19942814 June 199417 September 199417 daysComplete
19932227 June 199315 September 19939 daysComplete
1992910 July 199218 September 19923 daysComplete
19912725 May 199117 September 19919 daysComplete
1990264 July 199029 August 199012 daysComplete
19891827 June 198922 September 19894 daysComplete
19883013 June 198828 August 198815 daysComplete
19871431 May 198718 August 19873 daysComplete
19861716 June 198630 September 19865 daysComplete
1985186 July 19854 September 19853 daysComplete
1984348 June 198411 September 19846 daysComplete
19834912 June 198321 September 198313 daysComplete
19822026 June 19823 September 19824 daysComplete
19812516 June 198113 August 19817 daysComplete
19803425 June 198022 September 198013 daysComplete
19793110 May 19797 September 197910 daysComplete
19781728 June 197830 August 19785 daysComplete
19772325 May 19773 September 19776 daysComplete
1976338 June 197628 August 197611 daysComplete
19753018 June 197527 August 197512 daysComplete
1974153 July 197413 September 19743 daysComplete
1973349 June 19733 September 19738 daysComplete
1972133 July 197228 August 19725 daysComplete
19712026 June 19719 September 19714 daysComplete
1970195 July 197023 September 19708 daysComplete
19692614 June 19691 September 19696 daysComplete
19681930 June 196825 August 19686 daysComplete
19672216 June 196722 August 19674 daysComplete
19661628 June 196630 August 19663 daysComplete
19651329 June 196521 September 19654 daysComplete
19641024 May 196431 August 19644 daysComplete
19631725 June 196322 August 19636 daysComplete
1962411 June 19627 August 19622 daysComplete
19612613 June 196112 September 19615 daysComplete
19602125 June 19609 September 19604 daysComplete
19593328 May 195924 September 19599 daysComplete
1958131 July 195831 August 19583 daysComplete
19572415 June 195722 September 19573 daysComplete
19561614 June 195619 August 19563 daysComplete
19553819 June 19551 September 19559 daysComplete
19541022 June 19541 October 19542 daysComplete
1953216 June 19536 September 19536 daysComplete
19522926 June 19522 September 19528 daysComplete
1951168 July 195114 September 19514 daysComplete
195098 June 195029 August 19502 daysComplete
19493312 June 194929 August 194910 daysComplete
19482025 June 194829 August 19485 daysComplete
19472828 June 194715 September 19476 daysComplete
19461126 June 194610 August 19466 daysComplete
19452112 June 194525 September 19453 daysComplete
19442628 May 19442 September 19447 daysComplete
1943213 June 19437 September 19437 daysComplete
19421512 June 194223 August 19424 daysComplete
19411620 June 194117 September 19413 daysComplete
19401010 July 194031 August 19402 daysComplete
19391821 June 193916 September 19397 daysComplete
19382123 June 193817 August 19387 daysComplete
1937271 June 19373 September 19379 daysComplete
193678 July 19368 September 19361 daysComplete
Decade averages for Nights at or above 20 C (68 F) in Boston
DecadeAverage days per yearYears counted
1930s18.34
1940s20.110
1950s20.910
1960s17.410
1970s23.510
1980s25.910
1990s23.510
2000s24.510
2010s34.310
2020s34.06

Compare with your own threshold in the threshold explorer. Fahrenheit thresholds are converted to tenths of a degree Celsius once, rounding half up.

Download the Data

  • Data for Nights at or above 20 C (68 F) in Boston, by year: CSV or JSON. Field meanings are on the data page.

Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-18 (18 October 2026). Threshold counts are computed by this site from the threaded city record.

Data as of . Last revised (2026-10-18).