N2theBlue is now Nep2une Scuba Diving - basically a name change - same great people who ran N2theBlue.
Nep2une Scuba – Small Group Diving At Its Best
I've been in March, April, June, July, November, and December. June/July are going to be hot, but generally in the mid to high 80's year round. Water temp doesn't vary too much. I would say that diving is good year round, but I can attest to diving being good in all of the months I've been there!
Fredericksted on the west side, IMO, is the better side for diving - pier, wrecks, reef, calm water, and Nep2une Scuba is a few steps from the pier. Not really a night life to walk to. There are restaurants/beach bars in town and along the coast and trivia night (if one of the bars still has it.) Don't expect a real party atmosphere unless you're bringing the party.
Christiansted, on the north side, has a nice boardwalk with restaurants/bars along it. Still, don't expect a party atmosphere unless there is something special going on, such as Carnival or the Christmas Boat Parade. There will be more people here just because this is where the shops are, but night life is pretty dull. Diving on the north side is different than the west side - water can be a little rougher (at least in June) but there is interesting topography.
If the link works, you can see a part of the boardwalk looking across the water to Hotel on the Cay.
Official Page for Live St. Croix Web Cam | GoToStCroix.com
The Pink Condos (can find on FaceBook) are on the west side about a 10 minute walk from Frederiksted and a couple of beach bars if they are still open. The condos provide your own private snorkeling area and a great view of sunset.