Rain doesn't particularly trouble me or the camera, though rain on the lens front does; combined with fogging from the cold it can be quite a nuisance. If it's teeming down, I use a very tiny travel umbrella held above the camera when the exposure is made. During portage of the camera on the tripod in the rain, a waterproof nylon stuffsack (or better, a Hypalon seam-sealed bag) is slipped over the camera. One of these has yet to allow too much rain on the camera.