I've done Sea Pines. Not really interested in driving to Charleston or Savannah. What else is there to do in Hilton Head when it's raining?

Send the rain to Texas and solve both our problems!

Short answer to your question: Nothing

On the other hand, have you ever been to Savannah? It's a half-hour away...not exactly inconvenient. Charleston is a long haul from HH.

Savannah's got lots of good food and drink downtown, friendly people and plenty of history.

I find Hilton Head to have the worst cuisine in the Carolinas, so on days when you can't golf or do the beach scene -- I leave the island. Even Bluffton is an improvement.

The following response is predicated on the assumption that Savannah and Hilton Head experience the same type of weather. Since they are so close to each geographically, I imagine that they do, so...

Do as the locals do: Ignore the rain and go about your business as usual. This protocol comes from the fact that while Savannah experiences some extremely intense showers (seriously, I'm talking good old-fashioned 40-days-and-40-nights, biblical-type rain where you get a strange urge to start gathering up two of every critter... just in case), those showers tend to be of very short duration, usually 15 to 30 minutes, tops, and they're followed by clear skies and bright sunshine... at least until the next cloud passes over. For this reason the locals go right on with whatever plans they might have made when it's raining knowing that it will probably have stopped by the time they get where they're going.

THAT bad? All restaurants? Some of them, sure...

Beaufort or Savannah may not even have rain the same time that HHI does.

Shop Tons of stores....eat....open you eyes....lot to do...