Most people will try to avoid it but sooner or later every golfer finds themselves in the rain every once in a while. When this circumstance arises it is best to be prepared. When you are prepared, you will not worry about the rain as much and have a clear head.
When golfing in the rain keeping dry is the key. An umbrella and a towel is a must. Other rain gear like rain gloves, rain pants, and a rain jacket are very helpful also.
Change with the course. When the course starts to get wet and the rain is coming down the course plays differently. The ground is softer so this makes golf shots plug or stick close to where they first hit. This also means that the greens will be slower. The wet conditions will also decrease the spin that you can put of golf shots due to the water on the club face and golf ball.