Fog in Nantucket, MA

daily fog outlook & 2016–2026 climatology
Fog unlikely through Sunday (peak 3%). August typically brings about 26 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Nantucket Memorial Airport (KACK). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KACKNantucket Memorial Airport248 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 Nantucket fogs in

Fog here concentrates in July and June — about 248 hours in a typical year at KACK, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KACK station page.

Fog season

January: ~10 hJanFebruary: ~14 hFebMarch: ~18 hMarApril: ~17 hAprMay: ~26 hMayJune: ~41 hJunJuly: ~51 hJulAugust: ~26 hAugSeptember: ~21 hSepOctober: ~11 hOctNovember: ~5 hNovDecember: ~6 hDec
Fog season runs February through September, peaking in July; fog is mostly a 10 PM–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.