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Built 2026-10-19 (19 October 2026)

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

Seattle has had nights with a minimum temperature at or above 20 C (68 F) in 12 years, most in 2021 with 4. Days per year, season span, streaks and every date.

Key Facts for Seattle

  • Seattle has had nights with a minimum temperature at or above 20 C (68 F) in 12 years, 18 days in all.
  • The most in one year was 4 days in 2021.
  • In 2025, the latest year on file, there were 1 such days.
  • The earliest first date in a year was 26 June 2021.
  • The latest last date in a year was 2 September 1974.
  • The longest run inside a single year was 2 days in 2009.
  • 1 year with under 90 percent of days observed is left out of these rankings.

Days per Year

12 years, 18 days
Nights at or above 20 C (68 F) per year in Seattle Days per year in Seattle with a minimum temperature at or above 20 C (68 F). The line is the decade average. The most was 4 in 2021. Grey bars are years with under 90 percent of days observed, left out of rankings. 012341974: 11981: 11996: 12004: 12006: 12009: 22016: 12017: 22021: 42022: 12023: 22025: 119742023
Days per year in Seattle with a minimum temperature at or above 20 C (68 F). The line is the decade average. The most was 4 in 2021. 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 Seattle
YearDaysDecade average
197411
198111
199611
200411.3
200611.3
200921.3
201611.5
201721.5
202142
202212
202322
202512

Season Span

earliest 26 June, latest 2 September
First to last qualifying date each year in Seattle For each year, a bar from the first to the last day in Seattle meeting 20 C (68 F). Long bars mean a long season. 1974: 2 September 1974 to 2 September 19741981: 9 August 1981 to 9 August 19811996: 14 July 1996 to 14 July 19962004: 23 July 2004 to 23 July 20042006: 22 July 2006 to 22 July 20062009: 28 July 2009 to 29 July 20092016: 19 August 2016 to 19 August 20162017: 2 August 2017 to 3 August 20172021: 26 June 2021 to 13 August 20212022: 18 August 2022 to 18 August 20222023: 14 August 2023 to 15 August 20232025: 11 August 2025 to 11 August 2025197419962006201620212023JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day in Seattle meeting 20 C (68 F). Long bars mean a long season.
First to last qualifying date each year in Seattle
YearFirst dateLast date
19741974-09-021974-09-02
19811981-08-091981-08-09
19961996-07-141996-07-14
20042004-07-232004-07-23
20062006-07-222006-07-22
20092009-07-282009-07-29
20162016-08-192016-08-19
20172017-08-022017-08-03
20212021-06-262021-08-13
20222022-08-182022-08-18
20232023-08-142023-08-15
20252025-08-112025-08-11

Every Year

Nights at or above 20 C (68 F) per year in Seattle
YearDaysFirst dateLast dateLongest streak in yearCoverage
2025111 August 202511 August 20251 daysComplete
2023214 August 202315 August 20232 daysComplete
2022118 August 202218 August 20221 daysComplete
2021426 June 202113 August 20212 daysComplete
201722 August 20173 August 20172 daysComplete
2016119 August 201619 August 20161 daysComplete
2009228 July 200929 July 20092 daysComplete
2006122 July 200622 July 20061 daysComplete
2004123 July 200423 July 20041 daysComplete
1996114 July 199614 July 19961 daysComplete
198119 August 19819 August 19811 daysComplete
197412 September 19742 September 19741 daysComplete
Decade averages for Nights at or above 20 C (68 F) in Seattle
DecadeAverage days per yearYears counted
1970s1.01
1980s1.01
1990s1.01
2000s1.33
2010s1.52
2020s2.04

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 Seattle, 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 2026-10-17 (17 October 2026). Threshold counts are computed by this site from the threaded city record.

Data as of . Last revised (2026-10-17).