noun
last rain of the rainy season; final baiu rain
Refers to the heavy rain that often marks the end of the tsuyu (rainy season) in Japan, frequently accompanied by thunderstorms.
送り梅雨の激しい雷雨で、川が増水した。
The river swelled due to the violent thunderstorm of the last rain of the rainy season.
走り梅雨 is the early rain before the official start of the rainy season, contrasting with 送り梅雨 which marks its conclusion.
Compound of 送り (okuri, 'sending off') and 梅雨 (tsuyu, 'rainy season'), literally 'sending-off rain', referring to the rain that marks the departure of the rainy season.