Did this hike in mid March. We were the first car in the parking lot ~7AM. The first 2-ish miles have a decent amount of elevation gain. Unfortunately there was some dense fog in spots so we couldn't enjoy the views as much as we would have liked. The thermal river is really interesting. It was in the low 30's F when we were there, so we did our best to submerge our bodies entirely. It's almost more of a stream than a river (at least by my American standards). Getting out was definitely the worst part. Having to dry off and change while it was snowing was an interesting experience. 2 other couples came while we were in the water, and saw several more people hiking up on our way down. Get there early if you want some privacy.