Fog in Gravenhurst, ON

daily fog outlook & 2016–2026 climatology
Fog unlikely through Monday (peak 16%). August typically brings about 6 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Muskoka Airport (CYQA). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
CYQAMuskoka Airport88 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 Gravenhurst fogs in

Fog here concentrates in December and February — about 88 hours in a typical year at CYQA, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the CYQA station page.

Fog season

January: ~7 hJanFebruary: ~11 hFebMarch: ~11 hMarApril: ~6 hAprMay: ~4 hMayJune: ~3 hJunJuly: ~3 hJulAugust: ~6 hAugSeptember: ~7 hSepOctober: ~5 hOctNovember: ~10 hNovDecember: ~16 hDec
Fog season runs August through May, peaking in December; fog is mostly a 4 AM–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.