The western-edge effect
Chicago sits at the far western edge of the Eastern time zone, so its solar noon comes late — around 12:50 CST in winter and 13:30 CDT in summer. That makes Chicago's summer sunsets spectacularly late for its latitude: past 20:25 CDT in late June, with the winter solstice still delivering 9 hours 20 minutes of daylight.
Lake Michigan light
On the lakefront, the horizon is genuine water — the calculator's sunrise times are almost exactly what you see from North Avenue Beach. In winter, the sun rises over the lake to the southeast, and 'sunrise over frozen Lake Michigan' is one of the city's best photographic constants.