Station by station
When does the ground freeze in Illinois?
Each bar runs from the typical first freeze to the typical last thaw at that depth, the median over the station's complete winters on record, with the typical number of frozen days after it. Frost reaches the deeper probes later in the winter. A depth that froze in fewer than half of its winters has no typical dates. Stations: 3 typically freeze.
Champaign 9 SW
USCRNTypically freezes to 8 inches, not to 20.
2 in2 inches: typically frozen from Jan 6 to Feb 7, a median of 21 frozen days.21 days
4 in4 inches: typically frozen from Jan 7 to Feb 9, a median of 14 frozen days.14 days
8 in8 inches: typically frozen from Jan 19 to Feb 6, a median of 18 frozen days.18 days
20 inFroze in 0 of 3 winters, no typical dates
40 inFroze in 0 of 3 winters, no typical dates
Nov 3, 2026: Not frozen
Mason #1
SCANTypically freezes to 4 inches, not to 8.
2 in2 inches: typically frozen from Jan 23 to Feb 6, a median of 12 frozen days.12 days
4 in4 inches: typically frozen from Jan 21 to Feb 10, a median of 19 frozen days.19 days
8 inFroze in 1 of 5 winters, no typical dates
20 inFroze in 0 of 5 winters, no typical dates
40 inFroze in 0 of 5 winters, no typical dates
Nov 3, 2026: Not frozen
Shabbona 5 NNE
USCRNTypically freezes to at least 8 inches; the deeper probes have too few winters to say more.
2 in2 inches: typically frozen from Jan 7 to Mar 13, a median of 64 frozen days.64 days
4 in4 inches: typically frozen from Jan 20 to Mar 14, a median of 52 frozen days.52 days
8 in8 inches: typically frozen from Jan 21 to Mar 14, a median of 51 frozen days.51 days
20 inFroze in 0 of 1 winters, no typical dates
40 inFroze in 0 of 4 winters, no typical dates
Nov 3, 2026: Not frozen
A winter runs July to June. Our station readings come from one grass-covered site per station at five fixed depths, and often show shallower frost than regional figures.
