Fog in Johnstown, PA

daily fog outlook & 2016–2026 climatology
Fog unlikely through Monday (peak 8%). August typically brings about 7 hours of dense fog here.forecast cycle 2026-08-16T00:00:00Z · page rebuilt daily · live layers below update hourly

Measured at John Murtha Johnstown Cambria County Airport (KJST). Forecast percentages for this station have passed live verification.

Measuring station

stationairportfog hours/yrforecast
KJSTJohn Murtha Johnstown Cambria County Airport121 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 Johnstown fogs in

Fog here concentrates in January and December — about 121 hours in a typical year at KJST, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the KJST station page.

Fog season

January: ~16 hJanFebruary: ~13 hFebMarch: ~13 hMarApril: ~6 hAprMay: ~9 hMayJune: ~6 hJunJuly: ~5 hJulAugust: ~7 hAugSeptember: ~8 hSepOctober: ~11 hOctNovember: ~11 hNovDecember: ~16 hDec
Fog season is year-round, peaking in January; fog is mostly a 2 AM–9 AM phenomenon; typically thinning out by 3 PM; 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.