Steve -

On Monday I did the loop hike (S. Kaibab to river, return via Bright Angel), and conditions were great. Temps on the South Rim reach 70F, and temps near the river about 10 degrees higher. Spring has sprung, and lots of plants and bushes are in bloom, and wildlife is in abundance. Saw many elk and mule deer within a mile or so of the rim, and was thrilled to see a pair of CA condors soaring as I climbed up the canyon from the river. I posted a couple of photos on my FB timeline, but don't know how to link to them from this BB. Several potable water sources on the Bright Angel. It was a great hike - the S. Kaibab is on my short list of "Best Hikes of All Time". I don't think I'd want to attempt this loop much later in the year, at least as a dayhike. I found that I'd "lost" much of my acclimatization to high desert hiking I acquired from living seven years in Inyokern once I'd returned to New England during the past year and spent the winter hiking in NH's White Mtn NF.

Kevin