CYYW — Armstrong Airport

fog forecast & climatology · Armstrong city page · full 10-year analysis →
Fog unlikely through Saturday (peak 4%). September typically brings about 12 hours of dense fog here.forecast cycle 2026-09-04T13:00:00Z · page rebuilt daily · live layers below update hourly

Fog hours per year
66 h below CAT I minima (2016–2026 average)
Fog season
September and August
Typical fog event
~1 h once it forms (middle half 1–2 h, n=302)
Data through
2026-08-15 · machine-readable data.json

When this airport fogs in

In a typical year Armstrong Airport spends 66 hours below CAT I approach minima (visibility under ~½ mile or ceiling under 200 ft), concentrated in September and August. The strip above shows the hour-by-hour pattern for the current month from ten years of weather observations.

Fog season

January: ~3 hJanFebruary: ~1 hFebMarch: ~2 hMarApril: ~5 hAprMay: ~6 hMayJune: ~4 hJunJuly: ~7 hJulAugust: ~10 hAugSeptember: ~12 hSepOctober: ~9 hOctNovember: ~5 hNovDecember: ~4 hDec
Fog season runs April through January, peaking in September; fog is mostly a 5 AM–9 AM phenomenon; typically thinning out by 11 AM; a typical event lasts about 1 hour once it forms local time · 10-yr average

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.