Hi - We were on the last trip of the season last year - the very last week of August. I think the only thing we were a little unprepared for was how cold it could get - there was snow at the top of Big Sky - first time we've ever made snowballs in August. So if it's late August that you're going, I'd say just pack an extra layer. We also had some very chilly, wet weather during our glamping days and I really wished I had brought something warmer to sleep in. Beyond the weather, it was an amazing trip. Do everything that's offered - I was surprised that I really enjoyed the fly fishing lesson. I wish I had gone on the mountain bike trek, but the guides said it was pretty strenuous. My husband went and said I could have easily done it. When you're at the ranch, be sure to get up early to watch the horses come back after grazing free overnight in the high pastures - it's truly worth an early rise! Have a wonderful trip!!