Fog in Fort Smith, NT

daily fog outlook & 2016–2026 climatology
No fog signal in NWS guidance for the next 48 hours. August typically brings about 2 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Fort Smith Airport (CYSM). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring station

stationairportfog hours/yrforecast
CYSMFort Smith Airport26 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 Fort Smith fogs in

Fog here concentrates in October and September — about 26 hours in a typical year at CYSM, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the CYSM station page.

Fog season

January: ~2 hJanFebruary: ~0 hFebMarch: ~1 hMarApril: ~2 hAprMay: ~2 hMayJune: ~1 hJunJuly: ~1 hJulAugust: ~2 hAugSeptember: ~4 hSepOctober: ~6 hOctNovember: ~3 hNovDecember: ~2 hDec
Fog season is January, April, May, August, September, October, November, December, peaking in October; fog is mostly a 3 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.