With essentially no winter, long stretches of unseasonably mild weather, and now temperatures taking a drastic dip, this seasons thing is getting a little confusing around here. But rest assured, spring is indeed upon us. How do we know? Stephen Starr just sent word that SquareBurger starts slinging burgers and pouring Tastykake-laden milkshakes Thursday. As in the day after tomorrow! It kicks off the season just a few minutes after noon, following a ribbon cutting for the new Pavilion in Franklin Square, a recently completed 36-foot by 36-foot permanent venue that can be rented for special events, and doubles as Once Upon A Nation’s performance space. Philly Mini Golf, and the Philadelphia Park Liberty Carousel will also open Thursday for the season.