Fog in Grand Rapids, MI

daily fog outlook & 2016–2026 climatology
No fog signal in NWS guidance for the next 48 hours. August typically brings about 3 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Gerald R. Ford International Airport (KGRR). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring station

stationairportfog hours/yrforecast
KGRRGerald R. Ford International Airport46 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 Grand Rapids fogs in

Fog here concentrates in January and December — about 46 hours in a typical year at KGRR, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KGRR station page.

Fog season

January: ~11 hJanFebruary: ~5 hFebMarch: ~3 hMarApril: ~3 hAprMay: ~2 hMayJune: ~2 hJunJuly: ~1 hJulAugust: ~3 hAugSeptember: ~3 hSepOctober: ~3 hOctNovember: ~3 hNovDecember: ~7 hDec
Fog season runs August through April, peaking in January; fog is mostly a 4 AM–9 AM phenomenon; typically thinning out by 1 PM; 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.