bai-u
From Glossary of Meteorology
(Also called tsuyu.) In southern Japan and in parts of China, the name of the season of heaviest rainfall.
The bai-u season (June and early July in Japan, May to July in China) is the most important period for the cultivation and transplanting of rice.The bai-u rains are also called plum rains or mold rains, with reference to the season when plums ripen and to the effects of continued dampness.
