Jefferson County, Idaho · Frost dates
Jefferson County frost dates.
First-frost, last-frost, and growing-season length for Jefferson County, Idaho. Sourced from NOAA 1991-2020 Climate Normals.
Data confidence: high · USDA zone: 5b
32°F — light freeze
Last spring frost
- 10%
- 06-21
- 20%
- 06-17
- 50%
- 06-03
- 80%
- 05-21
- 90%
- 05-15
First fall frost
- 10%
- 08-30
- 20%
- 09-02
- 50%
- 09-11
- 80%
- 09-20
- 90%
- 09-24
28°F — killing freeze
Last spring freeze
- 10%
- 06-02
- 20%
- 05-26
- 50%
- 05-14
- 80%
- 05-06
- 90%
- 05-02
First fall freeze
- 10%
- 09-05
- 20%
- 09-11
- 50%
- 09-21
- 80%
- 10-01
- 90%
- 10-06
Growing season length (days, 28°F threshold)
- Short year
- 95
- Median
- 130
- Long year
- 157
Source NOAA station
HAMER 4 NW, ID US
12.0 mi · 30 yrs of record (1991–2020) · 4790 ft elev.
Data from HAMER 4 NW, ID US, 12 miles away with 30-year NOAA record (1991-2020).
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