I went ahead and booked tickets (award) SAN-LGA 6/29-7/6. Restaurant Week, Shakespeare in the Park, Coney Island, Brighton Beach, Central and Riverside Parks, Washingon Square, watching 4th of July Fireworks standing on the FDR, well, it just sounds too good!
Popping into air-conditioned shops (and restaurants and museums) sounds like a plan to escape the heat and humidity. We were in SW Louisiana this August, so I think we know what heat and humidity are like. All part of the ambience!