Fog in Hamilton, ON

daily fog outlook & 2016–2026 climatology
Fog unlikely through Monday (peak 7%). August typically brings about 4 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at John C. Munro Hamilton International Airport (CYHM). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
CYHMJohn C. Munro Hamilton International Airport127 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 Hamilton fogs in

Fog here concentrates in January and December — about 127 hours in a typical year at CYHM, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the CYHM station page.

Fog season

January: ~22 hJanFebruary: ~14 hFebMarch: ~15 hMarApril: ~11 hAprMay: ~10 hMayJune: ~4 hJunJuly: ~4 hJulAugust: ~4 hAugSeptember: ~8 hSepOctober: ~10 hOctNovember: ~7 hNovDecember: ~18 hDec
Fog season runs September through May, peaking in January; fog is mostly a 1 AM–10 AM phenomenon; 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.