February is usually frigid perfection for the ice rink at Millennium Park in downtown Chicago, a favorite winter stop for tourists and local families that stands in the shadow of the reflective sculpture known as the Bean.

On Tuesday morning, the rink was melting.

Under an intense sun and 70-degree air temperatures, water slowly trickled out of the empty rink, flooding the surrounding concrete. Baby birds splashed happily in the pools of water. The ticket counter was abandoned, apparently closed for the day.

Winter in Chicago — or the lack of it — reached an unnerving peak on Tuesday, when meteorologists predicted that the city could break a 48-year-old high-temperature record.

Around the city, it looked like summer: Apartment windows were pushed open to catch the warm breeze. Restaurants set up tables and chairs on sidewalks for al fresco lunch service, a rare sight in a Chicago February.

The lakefront was teeming with runners, cyclists and couples strolling hand in hand.

“We expected it would be very cold,” said Ana Marchal, 41, a doctor from Cádiz, Spain, who arrived in Chicago on Monday for a vacation with her husband, Rolf Hartmann.

They had figured on spending their holiday indoors, by shopping, visiting museums or attending Blackhawks and Bulls games.