Fog in Sion

daily fog outlook & 2016–2026 climatology
No fog forecast feed exists for this station. dense fog (visibility under a mile) is rare here in August (10-year average).

Measured at Sion Airport (LSGS). This station has climatology and live observations only.

Measuring station

stationairportfog hours/yrforecast
LSGSSion Airport20 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 Sion fogs in

Fog here concentrates in December and January — about 20 hours in a typical year at LSGS, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the LSGS station page.

Fog season

January: ~7 hJanFebruary: ~1 hFebMarch: ~0 hMarApril: ~0 hAprMay: ~0 hMayJune: ~0 hJunJuly: ~0 hJulAugust: ~0 hAugSeptember: ~0 hSepOctober: ~0 hOctNovember: ~3 hNovDecember: ~10 hDec
Fog season runs November through January, peaking in December; fog is mostly a 11 PM–11 AM phenomenon; 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.