Fog in Duluth, MN

daily fog outlook & 2016–2026 climatology
Fog possible — NWS guidance shows a fog signal in the next 48 hours. August typically brings about 16 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Duluth International Airport (KDLH). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring station

stationairportfog hours/yrforecast
KDLHDuluth International Airport178 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 Duluth fogs in

Fog here concentrates in September and December — about 178 hours in a typical year at KDLH, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KDLH station page.

Fog season

January: ~15 hJanFebruary: ~8 hFebMarch: ~13 hMarApril: ~20 hAprMay: ~15 hMayJune: ~14 hJunJuly: ~6 hJulAugust: ~16 hAugSeptember: ~29 hSepOctober: ~12 hOctNovember: ~10 hNovDecember: ~23 hDec
Fog season runs August through June, peaking in September; fog is mostly a midnight–10 AM phenomenon; typically thinning out by 3 PM; 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.