Fog in Portland, OR

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 Portland International Airport (KPDX). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring stations

stationairportfog hours/yrforecast
KPDXPortland International Airport75 h/yrverifying
KHIOPortland Hillsboro Airport170 h/yrverifying
KTTDPortland Troutdale Airport29 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 Portland fogs in

Fog here concentrates in November and December — about 75 hours in a typical year at KPDX, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KPDX station page.

Fog season

January: ~13 hJanFebruary: ~13 hFebMarch: ~3 hMarApril: ~0 hAprMay: ~0 hMayJune: ~0 hJunJuly: ~0 hJulAugust: ~0 hAugSeptember: ~3 hSepOctober: ~12 hOctNovember: ~18 hNovDecember: ~15 hDec
Fog season runs October through February, peaking in November; 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.