Every tree goes through times when it receives some damage to its leaves or branches. There are many reasons for this, but questions are often asked about the best time to prune dead or diseased branches from a tree.
The typical answer is "as soon as possible". However, you may not notice the damaged or dead branches until long after the damage has been done. If you are looking for the best season for this to be done, the answer is normally the late winter or early spring.