Fog in Lewiston, ID

daily fog outlook & 2016–2026 climatology
No fog signal in NWS guidance for the next 48 hours. dense fog (visibility under a mile) is rare here in August.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Lewiston Nez Perce County Airport (KLWS). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring station

stationairportfog hours/yrforecast
KLWSLewiston Nez Perce County Airport64 h/yrverifying

Fog is measured where instruments live — airports. Hours/yr = time below CAT I approach minima (visibility under ~½ mile or ceiling under 200 ft), the aviation definition of seriously dense fog.

When Lewiston fogs in

Fog here concentrates in December and November — about 64 hours in a typical year at KLWS, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KLWS station page.

Fog season

January: ~17 hJanFebruary: ~5 hFebMarch: ~3 hMarApril: ~1 hAprMay: ~1 hMayJune: ~0 hJunJuly: ~0 hJulAugust: ~0 hAugSeptember: ~0 hSepOctober: ~2 hOctNovember: ~17 hNovDecember: ~20 hDec
Fog season runs November through February, peaking in December; fog is mostly a midnight–9 AM phenomenon; typically thinning out by 11 AM; a typical event lasts about 1 hour once it forms local time · 10-yr average

Machine access: data.json · llms.txt · forecast verification. Not for operational use.