KJST — John Murtha Johnstown Cambria County Airport
fog forecast & climatology · Johnstown city page · full 10-year analysis →
Fog unlikely through Saturday (peak 7%). September typically brings about 8 hours of dense fog here.forecast cycle 2026-09-04T13:00:00Z · page rebuilt daily · live layers below update hourly
- Fog hours per year
- 121 h below CAT I minima (2016–2026 average)
- Fog season
- January and December
- Typical fog event
- ~1 h once it forms (middle half 1–2 h, n=678)
- Data through
- 2026-08-15 · machine-readable data.json
When this airport fogs in
In a typical year John Murtha Johnstown Cambria County Airport spends 121 hours below CAT I approach minima (visibility under ~½ mile or ceiling under 200 ft), concentrated in January and December. The strip above shows the hour-by-hour pattern for the current month from ten years of weather observations.
Fog season
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
Runway infrastructure
| end | approach lights | best approach | length | RVR |
|---|---|---|---|---|
| 05 | — | LPV | 4,387 ft | — |
| 23 | — | LPV | 4,387 ft | — |
| 15 | — | LPV | 7,004 ft | — |
| 33 | MALSR | CAT I | 7,004 ft | — |
From FAA NASR / curated AIP Canada research. Approach-light class and minima tier drive how low an approach can be flown — details in the chase board.
For flight operations
EFVS crews: the CHASE board ranks airports by live fog status, approach lighting, go-around height and flight time from your base. Forecast probabilities publish here per-airport once the calibrated model beats climatology on live verification — receipts on the scorecard. Methodology.
Sources: NOAA/NWS National Blend of Models guidance · METAR observations 2016–2026 (Iowa Environmental Mesonet) · FAA NASR. Machine access: data.json · llms.txt. Not for operational use.