Fog in Ottumwa, IA

daily fog outlook & 2016–2026 climatology
Fog unlikely through Sunday (peak 7%). August typically brings about 5 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Ottumwa Regional Airport (KOTM). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KOTMOttumwa Regional Airport60 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 Ottumwa fogs in

Fog here concentrates in January and December — about 60 hours in a typical year at KOTM, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KOTM station page.

Fog season

January: ~13 hJanFebruary: ~5 hFebMarch: ~5 hMarApril: ~3 hAprMay: ~4 hMayJune: ~2 hJunJuly: ~3 hJulAugust: ~5 hAugSeptember: ~5 hSepOctober: ~1 hOctNovember: ~5 hNovDecember: ~9 hDec
Fog season is January, February, March, May, August, September, November, December, peaking in January; fog is mostly a 3 AM–8 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.