The best window is mid-December to mid-April: hot, dry, with reliable trade winds and Atlantic water still warm enough to swim. Christmas and New Year are the peak; Easter is busy. May to early June is quieter and warmer, with the Pineapple Festival in Gregory Town in early June.
July to October is hot, humid, and inside the Atlantic hurricane season; many small hotels close in September. November is a gamble — usually fine, occasionally still stormy. Winds tend to be strongest in February and March, which is good for kiters but pushes Atlantic-side beaches around.