Frost/Freeze — San Juan River Basin, Colorado

2025-05-19 to 2025-05-20 · San Juan River Basin, Colorado

Event narrative

There is no available ASOS or AWOS site. The coldest temperature recorded at a RAWS site in the zone was 23F at the San Juan Portable RAWS #2, while the coldest temperature recorded at any sensor in the zone was 21F. Seven of the eight available sensors recorded temperatures at or below 32F for at least an hour, and the average duration of temperatures at or below 32F was 6.8 hours. Additionally, temperatures at or below 28F lasted for an average of 3.8 hours, marking this as a hard freeze event. No reports of crop losses or damages were received.

Wider weather episode

Another low pressure system with an associated cold front moved through the region in the days prior to this freeze event. The night of the event, clouds cleared and clear skies prevailed, along with generally light winds. Both of these promoted good radiational cooling, which combined with some modest cold air advection to drop temperatures below freezing in areas where vegetation was sensitive.

Source: NOAA Storm Events Database, event_id 1265832. Narrative written by the NWS forecast office that issued the report.