You don’t want to overheat in a thick wetsuit in tropical waters, and you also don’t want to freeze or risk hypothermia in a thin wetsuit in chilly temperatures.
Came to say the same, my last dive was 64f/18ishC in a 5mm wetsuit with hood and reef gloves and I was toasty and warm the whole time. My 9 year old snorkeled about for about a half hour in a 3mm suit in the same water without getting cold.
It’s not always down to body composition either, which I’ve seen before. I definitely wear my love of cake on the outside, while my daughter is a fit and healthy weight for her age and height.
2 points