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Frost Depth in Iowa: When the Ground Freezes

2 of 3 stations freeze at 2 inches in a typical winter, 1 of them to 8 inches or deeper.

Stations that typically freeze
2 of 3
Earliest typical freeze at 2 in
Dec 20
Latest typical thaw at 2 in
Mar 9

Station by station

When does the ground freeze in Iowa?

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: 2 typically freeze, 1 froze in some winters.

Ames

SCAN

Typically freezes to 4 inches, not to 8.

2 in
2 inches: typically frozen from Jan 19 to Mar 8, a median of 48 frozen days.48 days
4 in
4 inches: typically frozen from Jan 21 to Feb 24, a median of 24 frozen days.24 days
8 inFroze in 2 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

Des Moines 17 E

USCRN

Froze at 2 inches in 2 of 2 complete winters on record.

2 in
Each frozen winter's first freeze to last thaw at 2 inches.

2 in: froze in 2 of 2 · 4 in: froze in 1 of 2 · 8 in: froze in 1 of 2 · 20 in: froze in 0 of 2 · 40 in: froze in 0 of 2

Nov 3, 2026: Not frozen

Shagbark Hills

SCAN

Typically freezes to 8 inches, not to 20.

2 in
2 inches: typically frozen from Dec 20 to Mar 9, a median of 86 frozen days.86 days
4 in
4 inches: typically frozen from Dec 29 to Mar 9, a median of 64 frozen days.64 days
8 in
8 inches: typically frozen from Jan 12 to Feb 28, a median of 40 frozen days.40 days
20 inFroze in 1 of 5 winters, no typical dates
40 inFroze in 0 of 5 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.

More on frost depth

Where the ground is frozen today across the US · Iowa soil temperature · First frost and frost depth guide