Williamson County, Illinois · Frost dates
Williamson County frost dates.
First-frost, last-frost, and growing-season length for Williamson County, Illinois. Sourced from NOAA 1991-2020 Climate Normals.
Data confidence: high · USDA zone: 6a
32°F — light freeze
Last spring frost
- 10%
- 04-25
- 20%
- 04-20
- 50%
- 04-09
- 80%
- 03-30
- 90%
- 03-25
First fall frost
- 10%
- 10-10
- 20%
- 10-14
- 50%
- 10-22
- 80%
- 10-30
- 90%
- 11-02
28°F — killing freeze
Last spring freeze
- 10%
- 04-14
- 20%
- 04-08
- 50%
- 03-29
- 80%
- 03-18
- 90%
- 03-11
First fall freeze
- 10%
- 10-19
- 20%
- 10-24
- 50%
- 11-01
- 80%
- 11-11
- 90%
- 11-18
Growing season length (days, 28°F threshold)
- Short year
- 188
- Median
- 217
- Long year
- 252
Source NOAA station
CARBONDALE SEWAGE PLT, IL US
12.9 mi · 30 yrs of record (1991–2020) · 390 ft elev.
Data from CARBONDALE SEWAGE PLT, IL US, 12.9 miles away with 30-year NOAA record (1991-2020).
Bield Farm earns its predictions.
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