I honestly expected this to get around 80 degrees, but within a few hours in the sun it got to 104 degrees. I actually had to add in cold river water to get to a comfortable shower temp. I've never had these sun showers work well, but this one is an outperformer. It's so good I bought two and now just add this to a bucket of cold water for a long, hot shower while camping, after fishing, etc. I love this shower.