Fog in Savoy, IL

daily fog outlook & 2016–2026 climatology
Fog unlikely through Monday (peak 8%). 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 University of Illinois Willard Airport (KCMI). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KCMIUniversity of Illinois Willard Airport90 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 Savoy fogs in

Fog here concentrates in January and December — about 90 hours in a typical year at KCMI, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KCMI station page.

Fog season

January: ~19 hJanFebruary: ~11 hFebMarch: ~9 hMarApril: ~3 hAprMay: ~5 hMayJune: ~2 hJunJuly: ~4 hJulAugust: ~5 hAugSeptember: ~5 hSepOctober: ~4 hOctNovember: ~11 hNovDecember: ~13 hDec
Fog season is January, February, March, May, August, September, November, December, peaking in January; fog is mostly a midnight–8 AM phenomenon; typically thinning out by 11 AM; 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.