Forecast Illinois is the definitive portal for the Prairie State's weather and climate — built to make the official National Weather Service forecast fast, clean, and highway-clear for all 102 counties, from the Wisconsin line and the Chicago lakefront down 400 miles to Cairo, where the Ohio meets the Mississippi.
Illinois is long enough to hold two climates at once. The north takes Great Lakes winters — blizzards, lake-effect snow off Lake Michigan and polar-vortex cold — while the southern tip sits at the latitude of Richmond, catches Gulf moisture first, and lies in the path that gave the country its deadliest tornado. In between is the Grand Prairie, flat and open enough to hide nothing, drained by five big rivers that flood on other states' rain. Forecast Illinois is being built to tell that whole story — county by county, region by region.
The look borrows from the American Interstate system — the reflective paper, the green guide signs, the blue service signs, the brown recreation signs, and the red-white-and-blue route shields — set in Overpass, the typeface drawn from the Highway Gothic lettering on those signs. Illinois takes a warm prairie-loam paper and a blazing-star magenta accent — the color of the liatris that runs through what is left of the tallgrass, and a deliberate step away from the Chicago-flag blue of the metro site inside it.
Illinois is covered close-up by 9 region sites, each on its own subdomain of forecastillinois.com — the same maps, the same live radar and the same climate record as this site, drawn to one metro or region instead of the whole state, with a page for every city in it. They are part of Forecast Illinois, not separate sites: /about on any of them lands back here.
Illinois touches five states and all five are live: Forecast Wisconsin along the northern line, Forecast Iowa and Forecast Missouri across the Mississippi, Forecast Indiana along the Wabash and the eastern line, and Forecast Kentucky across the Ohio at the southern tip — each tinted in its own accent on the hero map and clickable from it. Forecast Chicago covers Chicagoland and the collar counties in its own right, and the Zone 1 tile hands off to it. The rest of the Forecast <State> network is part of the same system.
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