Fog in Hyannis, MA

daily fog outlook & 2016–2026 climatology
No fog signal in NWS guidance for the next 48 hours. 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 Cape Cod Gateway Airport (KHYA). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring station

stationairportfog hours/yrforecast
KHYACape Cod Gateway Airport79 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 Hyannis fogs in

Fog here concentrates in March and February — about 79 hours in a typical year at KHYA, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KHYA station page.

Fog season

January: ~6 hJanFebruary: ~10 hFebMarch: ~11 hMarApril: ~7 hAprMay: ~8 hMayJune: ~7 hJunJuly: ~4 hJulAugust: ~2 hAugSeptember: ~7 hSepOctober: ~6 hOctNovember: ~4 hNovDecember: ~5 hDec
Fog season runs September through July, peaking in March; fog is mostly a midnight–8 AM phenomenon; typically thinning out by 5 PM; 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.