Fog in Oshkosh, WI

daily fog outlook & 2016–2026 climatology
Fog unlikely through Sunday (peak 5%). 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 Wittman Regional Airport (KOSH). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KOSHWittman Regional Airport50 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 Oshkosh fogs in

Fog here concentrates in January and December — about 50 hours in a typical year at KOSH, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KOSH station page.

Fog season

January: ~12 hJanFebruary: ~8 hFebMarch: ~4 hMarApril: ~4 hAprMay: ~2 hMayJune: ~0 hJunJuly: ~1 hJulAugust: ~2 hAugSeptember: ~4 hSepOctober: ~2 hOctNovember: ~3 hNovDecember: ~10 hDec
Fog season is January, February, March, April, September, November, December, peaking in January; fog is mostly a 3 AM–10 AM phenomenon; typically thinning out by noon; 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.