Fog in Thunder Bay, ON

daily fog outlook & 2016–2026 climatology
Fog unlikely through Sunday (peak 7%). August typically brings about 9 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Thunder Bay International Airport (CYQT). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
CYQTThunder Bay International Airport59 h/yrlive forecast

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 Thunder Bay fogs in

Fog here concentrates in September and August — about 59 hours in a typical year at CYQT, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the CYQT station page.

Fog season

January: ~5 hJanFebruary: ~2 hFebMarch: ~2 hMarApril: ~4 hAprMay: ~4 hMayJune: ~5 hJunJuly: ~4 hJulAugust: ~9 hAugSeptember: ~11 hSepOctober: ~5 hOctNovember: ~3 hNovDecember: ~3 hDec
Fog season runs April through January, peaking in September; fog is mostly a 2 AM–9 AM phenomenon; typically thinning out by 11 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.