Cap10, I dunno if it's because my thermometers are strapped to my wrist (making them warmer), but I have always found it a bit hotter than that on average.
I know that we're both talking about the South side where due to Sun exposure, very little current, and shallow dive profiles, we are used to slightly warmer temps than other dive zones of Roatan, but not by much, maybe 1 or 2 degrees.
I have read January temps in the 0~15' zone usually in the 82+ degree range, especially so in the "Front Yard" of CCV, which is a very shallow lagoon with very little water transfer from the open Ocean. Of course, after a rain, things can drop down 1~2 degrees and when you hit that, it can make you twitch.
So, anyway, I'm calling it 78~82 degrees, but Cap10 is a veritable Pelagic Creature, known to plumb the abyss, returning from the deep cold depths with great tales of the briny deep. I'm basically a Sunfish and thrash around in the shallows like a Flounder.
Aqnother time period? Here's what my temp read last April....