The weather starts to get pretty nice in May. Memorial Day weekend I see people in the beach here. It is usually warm enough for that. Beginning of May you may want to get the upgrade, but by Memorial Day it is usually warm enough. This is currently the coldest winter, so who knows by then.
A lot of the condos (Summer Winds, Pebble Beach) have heated pools on site that do not require an upgrade. Evening activities...there is a Blackbeard's Ghost Walk in Beaufort that starts at dusk that is very entertaining. We took a group and went on it, and we enjoyed it a lot. Amos Mosquitos has karaoke every Thursday night, I believe.
The weather is pretty unpredictable that time of year. Most of the time it is warm, yet some days it's pretty cool at the beaches. You may want to go for the heated pool option, especially if it is early May. Night time is cool which makes the water temperature cold.
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