6 of 24 stations freeze at 2 inches in a typical winter, 3 of them to 8 inches or deeper.
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: 6 typically freeze, 2 froze in some winters, 15 never stayed at or below 32°F for 3 days running, 1 with too few winters to say.
Typically freezes to 8 inches, not to 20.
Typically freezes to 8 inches, not to 20.
Froze at 2 inches in 1 of 2 complete winters on record.
2 in: froze in 1 of 2 · 4 in: froze in 0 of 2 · 8 in: froze in 0 of 2 · 20 in: froze in 0 of 2 · 40 in: froze in 0 of 2
In 3 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: 35.4°F at 2 inches, 38.5°F at 4 inches, 42.1°F at 8 inches, 46.8°F at 20 inches and 51.1°F at 40 inches.
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: 33.4°F at 2 inches, 37.2°F at 4 inches, 42.1°F at 8 inches, 47.5°F at 20 inches and 56.7°F at 40 inches.
Typically freezes to 4 inches, not to 8.
2 complete winters on record, too few for typical dates.
Typically freezes to 2 inches, not to 4.
Typically freezes to at least 2 inches; the deeper probes have too few winters to say more.
In 3 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: 33.8°F at 2 inches, 32.7°F at 4 inches, 43.3°F at 8 inches, 49.3°F at 20 inches and 55.9°F at 40 inches.
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: 47.1°F at 2 inches and 49.8°F at 4 inches.
In 4 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: 39.9°F at 2 inches, 49.3°F at 4 inches, 54.1°F at 8 inches, 59.7°F at 20 inches and 65.8°F at 40 inches.
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: 31.8°F at 2 inches, 33.3°F at 4 inches, 31.8°F at 8 inches, 34.3°F at 20 inches and 37.4°F at 40 inches; a reading at or below 32°F lasted only a day or two.
Froze at 2 inches in 1 of 5 complete winters on record.
2 in: froze in 1 of 5 · 4 in: froze in 0 of 5 · 8 in: froze in 0 of 5 · 20 in: froze in 0 of 5 · 40 in: froze in 0 of 3
In 3 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: 41.2°F at 2 inches, 42.6°F at 4 inches, 46.2°F at 8 inches, 46.9°F at 20 inches and 48°F at 40 inches.
In 4 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: 39.2°F at 2 inches, 42.3°F at 4 inches, 44.8°F at 8 inches, 49.3°F at 20 inches and 55.6°F at 40 inches.
Typically freezes to 8 inches, not to 20.
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: 35.4°F at 2 inches, 38.7°F at 4 inches, 40.6°F at 8 inches, 40.3°F at 20 inches and 41.2°F at 40 inches.
In 4 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: 46.8°F at 2 inches, 47.5°F at 4 inches, 48.7°F at 8 inches, 51.4°F at 20 inches and 52.7°F at 40 inches.
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: 29.1°F at 2 inches, 30°F at 4 inches, 39.2°F at 8 inches, 41.5°F at 20 inches and 49.8°F at 40 inches; a reading at or below 32°F lasted only a day or two.
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: 46.2°F at 2 inches and 46.8°F at 4 inches.
In 4 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: 34.2°F at 2 inches, 39.7°F at 4 inches, 40.8°F at 8 inches, 45.3°F at 20 inches and 50.7°F at 40 inches.
In 4 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: 36.3°F at 2 inches, 39.9°F at 4 inches, 43.2°F at 8 inches, 48.6°F at 20 inches and 52.9°F at 40 inches.
In 4 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: 32.2°F at 2 inches, 32.7°F at 4 inches, 32.9°F at 8 inches, 33.4°F at 20 inches and 33.6°F at 40 inches.
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 · California soil temperature · First frost and frost depth guide