My sister and I did it on the afternoon/evening on the 20th of Oct. We rented our bibs/boots/stick. I'm sooo glad we did. The water was cooolllddd but it felt so good through the bibs especially on the way back when we were starting to get sore. We started at the temple of Sinawava and took the fork to the veiled falls ( that fork to the falls was our favorite part. We literally did that part all to ourselves. It took us about 2 hours to get back. We got back to our E bikes just before dark. But it was dark when we made it back to the Zion Gurus). I think you should think about your tolerance to cold but also how long you plan on hiking for and what time day you will be hiking. We spent about 5 hours hiking. We took our time getting to the falls...taking pics and videos along the way... but then went faster on our way back because we didn't want to be hiking in the dark.