I signed up for a liveaboard trip doing the keys starting at Key West. Middle of May. Wondering if I need to buy a heavier wet suit. Mine is a 3 mill, and have a skin as well, but no heavy wet suit. What can I expect for water temps?
Water temps can be found online
For example you can find Molasses Reef (key Largo) at:
http://www.ndbc.noaa.gov/station_page.php?station=mlrf1
or historical data for it here
http://www.ndbc.noaa.gov/view_text_file.php?filename=mlrf1h2008.txt.gz&dir=data/historical/stdmet/
at Molasses Reef in May, 15 2008, for example the water was 25c (or 77f)
a 3mm will be fine... but on a liveaboard you'll likely want a 2nd wetsuit or a warmer one. like Nash said, you'll get colder doing that many dives during a liveaboard. I typically wear more wetsuit on liveaboard trips than I do normal "day trip diving".
the 3mm should be fine though. But you might want to take a vest or shorty to "layer" if you need it. (or to wear by themselves.).
During summer liveaboard trips, I typically start my morning dive out in my 3mm. Why? because AC units on Liveaboard typically get "caught up" at night and freeze the cabin areas and you're a little chilled when you get up in the morning. that and the first dive the heat of the day hasn't picked up yet.
the 2nd ,3rd, etc dives I might switch to a shorty for example, then back to the 3mm for the night dive. (Of course this is how I do it and not how everyone does as everyone has different cold tolerences and different gear).
but I'll rarely carry my 5mm wetsuit on a summer liveaboard. (in south Florida or below).
One more thing to note, wearing too little thermal protection will also zap your engery levels on a liveaboard trip. Meaning you'll tire out easily from all the diving and the heat loss you body has. It zaps the engery that is required to regenerate the heat loss from your body.
hope that helps. Mike
