A route search system including an electronic control unit configured to perform: acquiring estimated weather information, the estimated weather information being information about weather that is estimated in a region where a candidate of a first route from a departure place to a destination place exists; acquiring reference weather information, the reference weather information being decided based on statistical information about weather information in a predetermined behavior range of a user; and searching the first route by preferentially selecting a first road over a second road, and outputting information about the first route, the first road being a road in a first region where the estimated weather information is not worse than the reference weather information, the second road being a road in a second region where the estimated weather information is worse than the reference weather information.