King County, Washington · Frost dates
King County frost dates.
First-frost, last-frost, and growing-season length for King County, Washington. Sourced from NOAA 1991-2020 Climate Normals.
Data confidence: high · USDA zone: 8b
32°F — light freeze
Last spring frost
- 10%
- 04-21
- 20%
- 04-13
- 50%
- 03-30
- 80%
- 03-13
- 90%
- 03-04
First fall frost
- 10%
- 10-22
- 20%
- 10-28
- 50%
- 11-07
- 80%
- 11-24
- 90%
- 12-01
28°F — killing freeze
Last spring freeze
- 10%
- 03-25
- 20%
- 03-17
- 50%
- 02-27
- 80%
- 02-06
- 90%
- 01-16
First fall freeze
- 10%
- 11-06
- 20%
- 11-12
- 50%
- 11-29
- 80%
- 12-19
- 90%
- 12-31
Growing season length (days, 28°F threshold)
- Short year
- 226
- Median
- 275
- Long year
- 349
Source NOAA station
SNOQUALMIE FALLS, WA US
3.5 mi · 30 yrs of record (1991–2020) · 440 ft elev.
Data from SNOQUALMIE FALLS, WA US, 3.5 miles away with 30-year NOAA record (1991-2020).
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