This paper describes Mokusei, an end-to-end Japanese version of our Jupiter weather information system. Mokusei delivers weather information over the phone through natural conversation with the user. For the most part, Mokusei uses the same components for recognition, understanding, and generation that Jupiter uses, and the database and the semantic frames for the weather information content are also shared. However, Mokusei motivated us to redesign our Genesis generation system, in order to improve the quality of translations of weather reports into Japanese. We also had to develop new ways to transcribe user utterances through morphological analysis. Mokusei is fully functional and has already been used for data collection with about 700 naive users. These data have been used for improvement and evaluation of Mokusei. This paper also presents the result of evaluating the current version of Mokusei.