KATW — Appleton International Airport

fog forecast & climatology · Appleton city page · full 10-year analysis →
Fog unlikely through Saturday (peak 15%). September typically brings about 3 hours of dense fog here.forecast cycle 2026-09-04T13:00:00Z · page rebuilt daily · live layers below update hourly

Fog hours per year
54 h below CAT I minima (2016–2026 average)
Fog season
December and February
Typical fog event
~2 h once it forms (middle half 1–3 h, n=162)
Data through
2026-08-15 · machine-readable data.json

When this airport fogs in

In a typical year Appleton International Airport spends 54 hours below CAT I approach minima (visibility under ~½ mile or ceiling under 200 ft), concentrated in December and February. The strip above shows the hour-by-hour pattern for the current month from ten years of weather observations.

Fog season

January: ~10 hJanFebruary: ~12 hFebMarch: ~5 hMarApril: ~6 hAprMay: ~4 hMayJune: ~1 hJunJuly: ~0 hJulAugust: ~2 hAugSeptember: ~3 hSepOctober: ~1 hOctNovember: ~1 hNovDecember: ~14 hDec
Fog season runs December through May, peaking in December; fog is mostly a 11 PM–10 AM phenomenon; typically thinning out by 1 PM; a typical event lasts about 2 hours once it forms local time · 10-yr average

Runway infrastructure

endapproach lightsbest approachlengthRVR
03MALSRCAT I8,003 ftRVR
21LPV8,003 ftRVR
12LPV6,502 ft
30MALSRCAT I6,502 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.