Boone County, Illinois · Frost dates
Boone County frost dates.
First-frost, last-frost, and growing-season length for Boone County, Illinois. Sourced from NOAA 1991-2020 Climate Normals.
Data confidence: high · USDA zone: 6a
32°F — light freeze
Last spring frost
- 10%
- 05-14
- 20%
- 05-09
- 50%
- 04-28
- 80%
- 04-19
- 90%
- 04-15
First fall frost
- 10%
- 09-28
- 20%
- 10-02
- 50%
- 10-12
- 80%
- 10-23
- 90%
- 10-27
28°F — killing freeze
Last spring freeze
- 10%
- 05-04
- 20%
- 04-28
- 50%
- 04-18
- 80%
- 04-08
- 90%
- 04-03
First fall freeze
- 10%
- 10-07
- 20%
- 10-15
- 50%
- 10-25
- 80%
- 11-02
- 90%
- 11-06
Growing season length (days, 28°F threshold)
- Short year
- 156
- Median
- 190
- Long year
- 217
Source NOAA station
MARENGO, IL US
11.7 mi · 30 yrs of record (1991–2020) · 815 ft elev.
Data from MARENGO, IL US, 11.7 miles away with 30-year NOAA record (1991-2020).
Bield Farm earns its predictions.
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