For those of you concerned about sea conditions as a predictor of beach conditions, you can check with one of the nautical weather apps to see wave height, direction, and period. As a full-time liveaboard, I use Predictwind, but it's more than a beachgoer is going to need, so you could check windguru.cz.

If the swell is under a meter and out of the east, places like Mullet will be calm. If it goes a bit southerly, it wraps around the southern coast and gets quite sporty around Simpson Bay, Maho, and Mullet. North affects Anse Marcel, Grand Case, Happy, Friars, etc.