Jefferson County, Iowa · Frost dates

Jefferson County frost dates.

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

Data confidence: high · USDA zone: 5a

32°F — light freeze

Last spring frost

10%
05-14
20%
05-08
50%
04-27
80%
04-17
90%
04-13

First fall frost

10%
09-27
20%
10-02
50%
10-12
80%
10-20
90%
10-25

28°F — killing freeze

Last spring freeze

10%
05-01
20%
04-26
50%
04-15
80%
04-05
90%
04-01

First fall freeze

10%
10-07
20%
10-13
50%
10-22
80%
10-30
90%
11-03

Growing season length (days, 28°F threshold)

Short year
159
Median
190
Long year
216

Source NOAA station

FAIRFIELD, IA US

1.2 mi · 30 yrs of record (19912020) · 740 ft elev.

Data from FAIRFIELD, IA US, 1.2 miles away with 30-year NOAA record (1991-2020).

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