1 of 2 stations freeze at 2 inches in a typical winter.
Station by station
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: 1 typically freeze, 1 never stayed at or below 32°F for 3 days running.
In 5 complete winters on record, 2-inch soil never stayed at or below 32°F for 3 days running.
Lowest daily reading at each depth, each from a different day: 32.9°F at 2 inches, 33.4°F at 4 inches, 33.4°F at 8 inches, 34.9°F at 20 inches and 34.5°F at 40 inches.
Typically freezes to 4 inches, not to 8.
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.
Where the ground is frozen today across the US · Michigan soil temperature · First frost and frost depth guide