I've used mine (OM-1n & 2n) in all weather for over 20 years and never had a problem. That said, I DO take care to use an umbrella, etc. in the rain, and to not let it get covered in snow if the camera is still warm. Care is also needed in hot dusty/sandy environments. If you want a care-free camera for use in the rain, I'd suggest a Nikonos.

Bruce