The weather should be clear and sunny. It should be in the high 70's and low 80's for almost the whole month of march. The averages have looked warm and clear in the past as well.
Ft. Lauderdale weather in March starts to get warmer. If you are lucky you will see highs in the 80s. The weather generally starts to warm up in March.
Having lived in Ft. Lauderdale for 4 years. My expereince in march was that it would be sunny with tempertures in the 70's with humidity that would not make you feel like you were always in the shower