I've dove both a 7/5 and a 5/3 in water as cool as 52 degrees. Both were comfy, the 7/5 I feel I probably could have gone colder even. The key to these for me was warm feet. I also dove the 7/5 at 52 degrees with thinner boots, and I froze my *** off, but with my 7mm boots on the next time I was comfy as can be... I also found that 55 degrees is my cutoff point for a hood too... 55 or colder, have to have it, 56 and above, it's very optional, and it takes a long time to get even cool without it. I honestly hate the hood, I almost feel claustraphobic with it over my ears (and I've never felt confined in any space)