{"city":"Chicago","region":"US-IL","country":"US","slug":"chicago-il","updated":"2026-08-16T02:45Z","window":{"start":"2016-01-01","through":"2026-08-15"},"stations":[{"icao":"KORD","name":"Chicago O'Hare International Airport","subCat1HoursPerYear":21,"forecast":"verifying"},{"icao":"KMDW","name":"Chicago Midway International Airport","subCat1HoursPerYear":13,"forecast":"verifying"}],"primaryStation":"KORD","forecast":{"covered":true,"public":false,"cycle":"2026-08-16T00:00:00Z","guidanceSignal":false,"wording":"No fog signal in NWS guidance for the next 48 hours. dense fog (visibility under a mile) is rare here in August."},"climatology":{"subCat1HoursPerYear":21,"fogSeasonPeakMonths":["January","December"],"medianEventHours":2,"season":{"summary":"Fog season runs December through March, peaking in January; fog is mostly a 11 PM\u20137 AM phenomenon; typically thinning out by 9 AM; a typical event lasts about 2 hours (local time, 10-year average).","months":["January","February","March","December"],"timeOfDay":"11 PM\u20137 AM","typicallyClearsBy":"9 AM"}},"links":{"page":"https://fogatlas.org/fog/city/chicago-il/","stationPages":["https://fogatlas.org/fog/kord/","https://fogatlas.org/fog/kmdw/"],"verification":"https://fogatlas.org/fog/scorecard/"}}