Fog in La Roche-sur-Yon

daily fog outlook & 2016–2026 climatology
No fog forecast feed exists for this station. August typically brings about 5 hours of dense fog here (10-year average).

Measured at La Roche-sur-Yon Les Ajoncs Airport (LFRI). This station has climatology and live observations only.

Measuring station

stationairportfog hours/yrforecast
LFRILa Roche-sur-Yon Les Ajoncs Airport153 h/yrclimatology

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 La Roche-sur-Yon fogs in

Fog here concentrates in December and November — about 153 hours in a typical year at LFRI, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the LFRI station page.

Fog season

January: ~22 hJanFebruary: ~16 hFebMarch: ~7 hMarApril: ~7 hAprMay: ~5 hMayJune: ~3 hJunJuly: ~4 hJulAugust: ~5 hAugSeptember: ~10 hSepOctober: ~23 hOctNovember: ~26 hNovDecember: ~29 hDec
Fog season runs September through February, peaking in December; fog is mostly a 1 AM–10 AM phenomenon; typically thinning out by noon; 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.