first snow of the season; first snowfall
Refers specifically to the first snow that falls in a given winter or season; common in weather reports and seasonal conversation.
今朝、町に初雪が降った。
The first snow of the season fell in town this morning.
今年の初雪は去年より早かった。
This year's first snowfall came earlier than last year's.
This year the first snow fell earlier than usual.
The first snow of the season was observed in Tokyo.
News of the first snowfall arrived from Hokkaido.