Fog in St Athan, Vale of Glamorgan

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 MOD St Athan (EGSY). This station has climatology and live observations only.

Measuring station

stationairportfog hours/yrforecast
EGSYMOD St Athan93 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 St Athan, Vale of Glamorgan fogs in

Fog here concentrates in January and December — about 93 hours in a typical year at EGSY, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the EGSY station page.

Fog season

January: ~20 hJanFebruary: ~14 hFebMarch: ~11 hMarApril: ~5 hAprMay: ~10 hMayJune: ~1 hJunJuly: ~3 hJulAugust: ~0 hAugSeptember: ~5 hSepOctober: ~5 hOctNovember: ~5 hNovDecember: ~18 hDec
Fog season runs September through May, peaking in January; fog here can hit at any hour of the day; 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.