I wouldn't worry too much about getting the coat a bit damp; after all, the sheep from which the coat was made probably spent more than a little time in the rain. (Ever been to Scotland, Ireland, Tasmania, or New Zealand?) Seriously, I believe that shearling coats are very different from the typical suede coats which are so sensitive to rain. If the finish is sueded, you might also treat the coat with a spray to make it more water resistant; when I bought a jacket some number of years ago, the store where I bought it sold something to spray on the jacket (akin to scotchgard, but it was a different product.) I might also suggest you phone a leather store or two to get their advice. You might try one or more of the following: Loewe (The Spanish leather company, not the German television manufacturer; store in Manhattan?) Overland Sheepskin (stores in Yountville/Napa Valley, California and Jackson, Wyoming) Searle (numerous stores in Manhattan).