Bottom temp (at 101 fsw) on my last dive earlier this week was 64 F and I was not uncomfortable in my 3/2mm full wetsuit. It is so easy to get into and out of that I prefer diving it when temperatures are tolerable. I would definitely be using it in temperatures in the mid- to upper-70s (like we had this summer and early fall), although at night I will now put on my 7mm because the air can be chilly on the ride home in my golf cart!
Your mileage may vary considerably since you possibly do not have the same amount of internal insulation (bioprene) as I carry.
Your mileage may vary considerably since you possibly do not have the same amount of internal insulation (bioprene) as I carry.