Fog in Derby, WA

daily fog outlook & 2016–2026 climatology
No fog forecast feed exists for this station. August typically brings about 3 hours of dense fog here (10-year average).

Measured at RAAF Base Curtin (YCIN). This station has climatology and live observations only.

Measuring stations

stationairportfog hours/yrforecast
YCINRAAF Base Curtin20 h/yrclimatology
YDBYDerby Airport12 h/yrclimatology

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 Derby fogs in

Fog here concentrates in September and April — about 20 hours in a typical year at YCIN, usually lasting ~1 h once it forms. Hour-by-hour patterns, live conditions and the forecast strip live on the YCIN station page.

Fog season

January: ~1 hJanFebruary: ~0 hFebMarch: ~3 hMarApril: ~3 hAprMay: ~0 hMayJune: ~1 hJunJuly: ~3 hJulAugust: ~3 hAugSeptember: ~4 hSepOctober: ~1 hOctNovember: ~0 hNovDecember: ~0 hDec
Fog season is March, April, July, August, September, peaking in September; fog is mostly a 4 AM–7 AM phenomenon; typically thinning out by 8 AM; 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.