Fog in Altoona, PA

daily fog outlook & 2016–2026 climatology
Fog unlikely through Monday (peak 9%). August typically brings about 10 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at Altoona Blair County Airport (KAOO). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KAOOAltoona Blair County Airport87 h/yrlive forecast

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 Altoona fogs in

Fog here concentrates in September and January — about 87 hours in a typical year at KAOO, usually lasting ~2 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KAOO station page.

Fog season

January: ~12 hJanFebruary: ~8 hFebMarch: ~5 hMarApril: ~3 hAprMay: ~7 hMayJune: ~3 hJunJuly: ~5 hJulAugust: ~10 hAugSeptember: ~12 hSepOctober: ~10 hOctNovember: ~4 hNovDecember: ~7 hDec
Fog season is year-round, peaking in January; fog is mostly a 2 AM–8 AM phenomenon; typically thinning out by 9 AM; a typical event lasts about 2 hours once it forms local time · 10-yr average

Machine access: data.json · llms.txt · forecast verification. Not for operational use.