Boise, Idaho — Persistent temperature inversions dominated weather conditions across southwest Idaho during January, leading to extended periods of valley fog, low cloud cover, and unusually dry conditions.
According to the National Weather Service office in Boise, a stable weather pattern remained in place for much of January 2026. The pattern resulted in below-normal precipitation across the region and above-normal temperatures in many locations.
Forecasters noted that while temperatures were generally warmer than average, valley locations experienced less warming due to cold air trapped beneath the inversion layer. This contributed to prolonged episodes of fog and low stratus clouds, particularly in lower elevations.
Snowfall totals were significantly below normal at low and mid elevations. In McCall, Idaho, just 6.6 inches of snow fell during January — the lowest January snowfall recorded there since 1985, according to NWS data.
Maps released by the Weather Service show widespread precipitation deficits across Idaho and surrounding areas, alongside positive temperature departures for much of the region throughout the month.
Meteorologists said inversion-driven patterns like those seen in January can suppress storm systems, limit snow accumulation, and worsen air quality in valleys due to stagnant conditions.
The National Weather Service stated that January’s weather summary is part of its routine monthly climate monitoring and does not indicate immediate hazards. Additional outlooks and updates will be provided as February conditions evolve.
For commuters and residents in valley communities, the prolonged fog episodes were among the most noticeable impacts of the month-long pattern.
