Fog in Sundsvall/ Härnösand

daily fog outlook & 2016–2026 climatology
No fog forecast feed exists for this station. August typically brings about 23 hours of dense fog here (10-year average).

Measured at Sundsvall-Härnösand Airport (ESNN). This station has climatology and live observations only.

Measuring station

stationairportfog hours/yrforecast
ESNNSundsvall-Härnösand Airport257 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 Sundsvall/ Härnösand fogs in

Fog here concentrates in November and September — about 257 hours in a typical year at ESNN, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the ESNN station page.

Fog season

January: ~21 hJanFebruary: ~23 hFebMarch: ~16 hMarApril: ~12 hAprMay: ~10 hMayJune: ~9 hJunJuly: ~11 hJulAugust: ~23 hAugSeptember: ~36 hSepOctober: ~36 hOctNovember: ~39 hNovDecember: ~26 hDec
Fog season runs July through May, peaking in November; fog is mostly a 8 PM–6 AM phenomenon; typically thinning out by 9 AM; 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.