Jefferson County, Colorado · Frost dates

Jefferson County frost dates.

First-frost, last-frost, and growing-season length for Jefferson County, Colorado. Sourced from NOAA 1991-2020 Climate Normals.

Data confidence: high · USDA zone: 5a

32°F — light freeze

Last spring frost

10%
06-10
20%
06-02
50%
05-23
80%
05-14
90%
05-09

First fall frost

10%
09-06
20%
09-13
50%
09-22
80%
09-30
90%
10-03

28°F — killing freeze

Last spring freeze

10%
05-22
20%
05-18
50%
05-09
80%
05-02
90%
04-29

First fall freeze

10%
09-18
20%
09-24
50%
10-02
80%
10-10
90%
10-15

Growing season length (days, 28°F threshold)

Short year
119
Median
146
Long year
169

Source NOAA station

EVERGREEN, CO US

5.5 mi · 30 yrs of record (19912020) · 6985 ft elev.

Data from EVERGREEN, CO US, 5.5 miles away with 30-year NOAA record (1991-2020).

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