I've been to a few pride parades and events in the past ten years and I find them as a semi-consistent place to spot public pissing. Not as much as a St. Patrick's Day or anything like that but still you'll likely see a few people peeing in the street every year.
What I'm more interested in finding more of, is sort of organized piss kink at pride. Pride events will regularly feature bdsm and fetish wear and I know the Folsom Street Fair in San Francisco features an inflatable pool where peo