Fog in Oakland, CA

daily fog outlook & 2016–2026 climatology
Fog possible — NWS guidance shows a fog signal in 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 San Francisco Bay Oakland International Airport (KOAK). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring station

stationairportfog hours/yrforecast
KOAKSan Francisco Bay Oakland International Airport18 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 Oakland fogs in

Fog here concentrates in December and January — about 18 hours in a typical year at KOAK, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KOAK station page.

Fog season

January: ~4 hJanFebruary: ~2 hFebMarch: ~2 hMarApril: ~0 hAprMay: ~0 hMayJune: ~0 hJunJuly: ~0 hJulAugust: ~0 hAugSeptember: ~1 hSepOctober: ~1 hOctNovember: ~3 hNovDecember: ~6 hDec
Fog season runs November through March, peaking in December; fog is mostly a 3 AM–8 AM phenomenon; typically thinning out by 10 AM; a typical event lasts about 2 hours once it forms local time · 10-yr average

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