Fog in San José (Alajuela)

daily fog outlook & 2016–2026 climatology
No fog forecast feed exists for this station. August typically brings about 4 hours of dense fog here (10-year average).

Measured at Juan Santamaría International Airport (MROC). This station has climatology and live observations only.

Measuring station

stationairportfog hours/yrforecast
MROCJuan Santamaría International Airport29 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 San José (Alajuela) fogs in

Fog here concentrates in November and June — about 29 hours in a typical year at MROC, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the MROC station page.

Fog season

January: ~0 hJanFebruary: ~0 hFebMarch: ~0 hMarApril: ~0 hAprMay: ~3 hMayJune: ~5 hJunJuly: ~3 hJulAugust: ~4 hAugSeptember: ~4 hSepOctober: ~4 hOctNovember: ~6 hNovDecember: ~0 hDec
Fog season runs May through November, peaking in November; fog is mostly a 8 PM–4 AM phenomenon; typically thinning out by 7 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.