which is better shrinkwrap the boat white outside in the sun or cover it and store inside a dark un heated building.my thought was shrinkwrap and the sun could keep it drier.any help please!

PUT THE BOAT INSIDE STORAGE. I can't tell you how many threads I've read about people having parts stolen off of their boat while sitting outside somewhere

I would think that drastic temp changes would be worse. How about a warm wet day in Jan with lots of condensation? I think inside is always better.

Inside

Outside shrinkwrapped is better unless you have a garage to store it in. Most marina dry rack buildings are metal buildings with condensation problems. Plus the pigeons and other birds not to mention the diesel forklift exhaust covering everything. But it must be shrink wrapped correctly, vented properly and not just tied so it can chaff the side of the boat. A climate controlled garage is the best bet.

Make sure the floor is paved, no gravel or Ag Lime in the storage building, otherwise store it outside. Lots of moisture and corosion in a non paved floor.

thank you all I will shrinkwrap and keep it out side.

Is the sun always shining where you intend to store your boat so you have a nice constant temperature outside ? I would be surprised if that is the case.
If you have access to indoor storage in a well insulated and dry place there is no doubt in my mind that I would store it inside. It does not matter if the inside storage is not heated. The main thing is that it is dry and if insulated the temperature variations will be minimal.

This is correct as far as I am concerned. Most indoor storage that is not completely sealed and have climate control has alot of moisture and condensation, plus the forklift fumes. I work for a marina and have access to either for the last 4 years and always just shrink wrap mine myself and keep it outside. Just make sure that who ever does it puts vents in the shrink wrap and also mold and mildew bags in there They should do this without you having to ask but just make sure it is done. You can get the mildew bags for a few bucks at a marina or Walmart, I would throw a few of them in there when you drop off the boat to be done. I have done hundreds of shrinkwraps and will tell you I know I have forgot mildew bags a few times, just an honest mistake when you get swamped with work at a sudden freeze and everyone wants there boat done yesterday.