Here is a
SXM weather across the year link to an interesting and informative site.
This shows that the Trade Winds and the 18* North Latitude combine to keep the daily highs and lows within a very narrow range year around.
Concerning the rain, St Martin, Anguilla, and St. Barts are the first land masses the trade winds encounter after blowing across the Atlantic since leaving the Azores. When those moisture laden winds hit the mountains they rise in altitude and release moisture in the form of light rainshowers.
On most days it will rain a little while SOMEWHERE on the island for a short period of time, hence the "rain every day" forecasts... There is nothing like the all day rains we experience here in the US mid atlantic states when a warm front moves in.
Check out the data in the link.
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