Since the pools are heated, I've seen people in them when it's 45 degrees out.
However, I'm guessing that you're asking if it will be warm enough outside to justify an afternoon by the pool. Depends. The weather is still in that transition period where it could be in the 80s or it could be in the 60s. I went over the first week of March a couple years back, and our week started with lows in the 40s to ending the week with highs in the 80s. You should get at least a couple of good days to swim on your vacation, though. Have fun!