Sparrow didn't usually have cause to go to London but he'd had to conduct some business in Gringotts. Now, he was mostly wandering around the Alley since he figured he might as well make a day of it. He figured he would get something to eat at the Leaky and then take the Knight Bus back to Hogsmeade. There were all sorts of people wandering in and out and the Alley and Sparrow was content to people watch for the moment.
"Nice day, huh?" He said politely when someone else took a seat on the fountains edge. It was somewhat hot in the Alley so he couldn't blame the other person for needing to take a little rest.