For the first time since it opened in February, IO Urban Roofscape (Godfrey Hotel, 127 W. Huron St., River North, 312-649-2000) opened its indoor-outdoor rooftop bar to the elements this past weekend. Unsurprisingly, Chicagoans thronged the posh lounge, a sign of things to come as the city crawls toward summer.

Between the patio's purple glow, chic white couches and canopies, and a lot of exposed skin, the place may as well have been South Beach. Guests sipped on juleps made with mint-olive shaved ice and whiskey sours with seasonal fruit on couches surrounding fire pits and overlooking the skyline.

In inclement weather, part of the patio can be enclosed with glass doors and a retractable roof—but on a night like Saturday, the first true break from a chilly, stir-crazy winter, everyone wanted to be out. The line was out the door all evening long.

Here's what we saw while scoping out the place.