We are March break regulars. Weather can be variable, but more often hot than cool, but we have experienced both.
Our last two March trips have been very hot, temps in the 90's, so definitely pool weather. The couple of cooler trips we have had were mostly light sweater and jeans weather with temps struggling to hit 70, but there were always a couple of days that were still sunny and warm enough for the pool. On average I would guess that daytime highs reach around 80 in March, obviously a bit more in April. We have never experienced much rain in March, with only two really full rainy days that I recall in many trips, there have been cloudy days with quick showers though.