Dont you have to worry about humidity after the rain,,ruining your paint job? I would also agree with the booth idea,,although i have done a paint job right out in the open backyard style,in a dusty city,,L.A.,,and to my amazement,The final job came out dust free,lucky maybe,or maybe i applied the clear right away after tacking BC,and the clear cured fast enough to color sand off any dust that might have stuck-the end result after polishing was a show shine finish-i wouldnt rcommend outside painting,but if thats all you have then just be real careful,,,good luck