What Richard said. I have never had a problem with my OM1/2s in inclement weather, but they are not weatherproof. I wouldn't shoot with them in a pouring rain unless I had the controls in something such as a ziplock bag. That said, the nice thing about the OM1 is that it's an all mechanical camera. Even without the meter, you can shoot at any shutter speed. I think the OM-2SP might be most at risk given the amount of electronics stuffed inside. The OM-2SP is more closely related to the OM-4 than the OM-2(n).

Earl