Car wont Start on 1993 Volvo 940

Every time we have a rainy day my car will not start. The battery is less than 1 yr old. When the sun comes out a day later the car will start right up and drive for weeks at a time and then when it rains again the car will not start.

2 answers
Have you checked the distributor cap? Is it cracked, allowing moisture in? I had that happen once, and the car wouldn't start.
What are the symptoms? Does the engine spin when turning the key?