Going to a funeral in July?

I live on the east coast, where today it is 100 degrees with a heat index of 98 degrees. in a half hour(at 5 o clock) i'm going to be on my way to a funeral which takes place at 6. it still should be very hot out. the only thing I have pretty much appropriate for a funeral is brown jean-like pants, i'm wearing a sleeveless purple top, with a tank top under that b/c the arm holes are big and show too much. i'm afraid i'm going to burn up out there...any quick suggestions?