A sure sign of spring? News of new rooftop bars sprouting up around town. Today we have word that the Flatiron Hotel will launch Toshi's Penthouse Bar and Rooftop, a spinoff of the Toshi's Living Room, a live music venue off the lobby of the property. This watering hole will have awesome view of the Empire State Building and will be open Monday through Saturday starting in May. There's an interior space for rainy nights and the property is pushing the joint for private shindigs. File this as yet another reason we're excited to the arrival of spring (9 West 26th St.).