Frost/Freeze in San Juan River Basin, Colorado

Five of the seven reporting stations available for verification recording temperatures at or below 32F for at least 3 hours, and four of those seven recorded temperatures at or below 28F for at least three hours. This means that at least 50% of the zone experienced a season-ending freeze event. The lowest temperature recorded was 25F, while the lowest recorded at the San Juan Portable RAWS was 27F. Minimum temperatures ranged from 25F to 32F. Temperatures at or below 32F lasted for on average 6 hours, with a maximum of 10 hours and a minimum of 0. Temperatures at or below 28F lasted for on average 3 hours, with a maximum of 6 hours and a minimum of 0.

Dry air over southwestern Colorado led to clear skies. Overnight, a trough moved through the region, and the associated cold front dropped temperatures to below freezing for much of the area. Under this pattern, three zones experienced a season ending freeze.