We were down in Marathon in the first week of February of this year. The weather had just broke from being cold according to the locals. Air temps in the upper 70's to low 80's during the day, upper 60's at night, very pleasant.
Water temps were running in the low 70's on the surface with temps in the mid 60's at 80'.
I generally wore a 5mil full on the first dive of the day and put a 3mil shorty over that on the second and third dives of the day with no hood, and was comfortable until the later dives. My wife wore her hood all the time, but she gets cold easy:mean: .