It rains in southern California???
Once it clears up take a look at your signal levels. Your dish may need reaiming or there may be connectors that need to be replaced if they are allowing water into the system. If you have problems with the dish they should be straightened out as part of your Hopper/Joey install (which you asked about in another thread).
Some people seem to get rain fade all the time - if this is your first time either you are new to satellite or are not one of those people.