The only reason I sometimes prefer a 5 mm Full in winter in Cozumel is because the boat ride in to spend the surface interval on the shore can be chilly if it's cloudy/rainy. But in Bonaire there is no boat ride issue. I have never been chilly in a 3/2 Full in winter, even when it has been cloudy/rainy. Some of my dive companions dive in shorties or less.