Fog in Lebanon, NH

daily fog outlook & 2016–2026 climatology
Fog possible — NWS guidance shows a fog signal in the next 48 hours. August typically brings about 57 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Lebanon Municipal Airport (KLEB). This station is in forecast verification — percentages publish when it clears the accuracy bar.

Measuring station

stationairportfog hours/yrforecast
KLEBLebanon Municipal Airport376 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 Lebanon fogs in

Fog here concentrates in September and October — about 376 hours in a typical year at KLEB, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KLEB station page.

Fog season

January: ~12 hJanFebruary: ~9 hFebMarch: ~13 hMarApril: ~16 hAprMay: ~18 hMayJune: ~29 hJunJuly: ~39 hJulAugust: ~57 hAugSeptember: ~76 hSepOctober: ~63 hOctNovember: ~30 hNovDecember: ~21 hDec
Fog season runs June through December, peaking in September; fog is mostly a 2 AM–8 AM phenomenon; typically thinning out by 9 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.