you really should wait 3 days after rain before using an oil primer. it just doesnt adhere well to raw, wet wood. you can literally peel off oil based paint/primer that has been applied to wet wood.

you might be able to borrow a mositure meter from your local paint store that can help you to determine when you can paint. or you may look into getting a water based primer. Water based primers do not work as well on raw wood, especially if its redwood or cedar, but you can use water based primers on wet wood on a dry day. you just need to dry it to the touch with towells or cloths, and point a fan at the side of the shed your are painting.

if you used brand new wood that still has a mill glaze on it, you might just be able to wait until you get a nice week of weather, even if thats not till early spring.

 

I don't think I would be applying ANY primer,oil or latex, till it was COMPLETLY dry. I don't buy the statement that you can apply latex after just towling dry.:no: You MIGHT get it to stick but why take the chance?