we've been going down around Xmas and returning after New Year's for some years now, although we skipped a couple of years due to Irma (went to Barbados instead)....the holidays don't affect much as far as places being open, although most (all?) grocery stores are closed Xmas day (so best to buy any groceries you may need by Xmas eve) , but plenty of restaurants/bars open so you won't starve or dehydrate....Christmas is a big beach day, we usually go to Mullet....Boxing day forward everything pretty much back to normal

usually on SBH for several days before & after New Year's, but last year due to COVID we stayed on SXM...hung out in Maho for the festivities....watched the fireworks, listened to a band at Driftwood, and had a great time.... didn't catch Covid

Christmas winds are definitely a thing...temps are still plenty warm, and the water is cool and refreshing but not uncomfortable, but there is usually a pretty noticeable wind, especially on Orient