Fog in Groton, CT

daily fog outlook & 2016–2026 climatology
Fog unlikely through Sunday (peak 2%). 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 Groton New London Airport (KGON). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KGONGroton New London Airport88 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 Groton fogs in

Fog here concentrates in May and June — about 88 hours in a typical year at KGON, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KGON station page.

Fog season

January: ~6 hJanFebruary: ~10 hFebMarch: ~11 hMarApril: ~7 hAprMay: ~13 hMayJune: ~13 hJunJuly: ~10 hJulAugust: ~2 hAugSeptember: ~3 hSepOctober: ~3 hOctNovember: ~2 hNovDecember: ~6 hDec
Fog season runs December through July, peaking in May; fog is mostly a 4 AM–8 AM phenomenon; typically thinning out by noon; 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.