Fog in Belleville, IL

daily fog outlook & 2016–2026 climatology
Fog unlikely through Monday (peak 3%). August typically brings about 1 hour of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Scott AFB/Midamerica Airport (KBLV). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KBLVScott AFB/Midamerica Airport45 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 Belleville fogs in

Fog here concentrates in December and January — about 45 hours in a typical year at KBLV, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KBLV station page.

Fog season

January: ~6 hJanFebruary: ~5 hFebMarch: ~3 hMarApril: ~3 hAprMay: ~3 hMayJune: ~1 hJunJuly: ~4 hJulAugust: ~1 hAugSeptember: ~2 hSepOctober: ~4 hOctNovember: ~5 hNovDecember: ~8 hDec
Fog season is January, February, March, April, May, July, September, October, November, December, peaking in December; fog is mostly a 1 AM–8 AM phenomenon; typically thinning out by 10 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.