noun
southerly wind at the start of the rainy season
A specific seasonal wind term used in weather or literary contexts; refers to the warm, moist southerly wind that blows as the rainy season (梅雨) begins.
黒南風が吹き始めると、梅雨入りが近い。
When the kurohae starts blowing, the rainy season is near.
南風 is a general term for a southerly wind, while 黒南風 specifically refers to the wind at the onset of the rainy season.
The term combines 黒 (black/dark) and 南風 (southerly wind), likely referring to the dark, rain-bearing clouds associated with the early rainy season. The exact historical origin is uncertain.