Station by station
When does the ground freeze in Colorado?
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: 8 typically freeze.
Boulder 14 W
USCRNTypically freezes at every depth measured, down to 4 inches.
2 in2 inches: typically frozen from Nov 19 to Apr 14, a median of 136 frozen days.136 days
4 in4 inches: typically frozen from Nov 23 to Apr 3, a median of 123 frozen days.123 days
Nov 3, 2026: Not frozen
Cortez 8 SE
USCRNTypically freezes to 8 inches, not to 20.
2 in2 inches: typically frozen from Dec 23 to Feb 11, a median of 47 frozen days.47 days
4 in4 inches: typically frozen from Dec 27 to Jan 21, a median of 16 frozen days.16 days
8 in8 inches: typically frozen from Jan 11 to Jan 20, a median of 9 frozen days.9 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
CPER
SCANTypically freezes to 20 inches, not to 40.
2 in2 inches: typically frozen from Nov 29 to Feb 23, a median of 55 frozen days.55 days
4 in4 inches: typically frozen from Dec 15 to Feb 23, a median of 40 frozen days.40 days
8 in8 inches: typically frozen from Jan 3 to Feb 15, a median of 39 frozen days.39 days
20 in20 inches: typically frozen from Jan 12 to Feb 20, a median of 24 frozen days.24 days
40 inFroze in 0 of 4 winters, no typical dates
No current reading
Dinosaur 2 E
USCRNTypically freezes to 8 inches, not to 20.
2 in2 inches: typically frozen from Nov 25 to Feb 24, a median of 87 frozen days.87 days
4 in4 inches: typically frozen from Dec 14 to Feb 24, a median of 50 frozen days.50 days
8 in8 inches: typically frozen from Jan 11 to Feb 22, a median of 26 frozen days.26 days
20 inFroze in 2 of 5 winters, no typical dates
40 inFroze in 0 of 5 winters, no typical dates
Nov 3, 2026: Not frozen
La Junta 17 WSW
USCRNTypically freezes to 4 inches, not to 8.
2 in2 inches: typically frozen from Dec 30 to Feb 6, a median of 29 frozen days.29 days
4 in4 inches: typically frozen from Jan 23 to Jan 30, a median of 7 frozen days.7 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
Montrose 11 ENE
USCRNTypically freezes to 8 inches, not to 20.
2 in2 inches: typically frozen from Nov 26 to Mar 23, a median of 101 frozen days.101 days
4 in4 inches: typically frozen from Dec 19 to Mar 9, a median of 62 frozen days.62 days
8 in8 inches: typically frozen from Jan 14 to Mar 4, a median of 47 frozen days.47 days
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
Nunn #1
SCANTypically freezes to 8 inches, not to 20.
2 in2 inches: typically frozen from Nov 28 to Feb 23, a median of 54 frozen days.54 days
4 in4 inches: typically frozen from Dec 18 to Feb 11, a median of 40 frozen days.40 days
8 in8 inches: typically frozen from Jan 10 to Feb 21, a median of 16 frozen days.16 days
20 inFroze in 2 of 4 winters, no typical dates
40 inFroze in 0 of 4 winters, no typical dates
Nov 3, 2026: Not frozen
Nunn 7 NNE
USCRNTypically freezes to 20 inches, not to 40.
2 in2 inches: typically frozen from Dec 16 to Feb 24, a median of 53 frozen days.53 days
4 in4 inches: typically frozen from Jan 1 to Feb 24, a median of 28 frozen days.28 days
8 in8 inches: typically frozen from Jan 9 to Feb 12, a median of 28 frozen days.28 days
20 in20 inches: typically frozen from Jan 12 to Jan 24, a median of 12 frozen days.12 days
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.
