It rained on me during a recent trip to Zion NP. Unlike the short light showers I've experienced in the past, this was a persistent and often heavy rain. My first hike was to the Northgate Peaks in the Kolob Terrace area and it rained almost the entire time. I decided it was too dangerous to tackle the slickrock on West NorthGate Peak, so I'll do that on another trip. Here's a shot along the trail from under a tree. It was still a nice hike.
It's hard to see, but on the east side of the park, the water was running off the slickrock in sheets.