Fog in Sudbury, ON

daily fog outlook & 2016–2026 climatology
Fog unlikely through Monday (peak 7%). August typically brings about 8 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Sudbury Airport (CYSB). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
CYSBSudbury Airport138 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 Sudbury fogs in

Fog here concentrates in December and November — about 138 hours in a typical year at CYSB, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the CYSB station page.

Fog season

January: ~10 hJanFebruary: ~11 hFebMarch: ~15 hMarApril: ~13 hAprMay: ~5 hMayJune: ~4 hJunJuly: ~4 hJulAugust: ~8 hAugSeptember: ~14 hSepOctober: ~14 hOctNovember: ~17 hNovDecember: ~24 hDec
Fog season runs August through April, peaking in December; fog is mostly a 3 AM–10 AM phenomenon; typically thinning out by 2 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.