Fog in Mariehamn

daily fog outlook & 2016–2026 climatology
No fog forecast feed exists for this station. August typically brings about 8 hours of dense fog here (10-year average).

Measured at Mariehamn Airport (EFMA). This station has climatology and live observations only.

Measuring station

stationairportfog hours/yrforecast
EFMAMariehamn Airport166 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 Mariehamn fogs in

Fog here concentrates in March and February — about 166 hours in a typical year at EFMA, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the EFMA station page.

Fog season

January: ~17 hJanFebruary: ~22 hFebMarch: ~28 hMarApril: ~13 hAprMay: ~10 hMayJune: ~4 hJunJuly: ~7 hJulAugust: ~8 hAugSeptember: ~17 hSepOctober: ~11 hOctNovember: ~14 hNovDecember: ~14 hDec
Fog season runs July through May, peaking in March; fog is mostly a 11 PM–10 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.