Throughout the year; year-round. Used for things that continue regardless of season (e.g., year-round operation, year-round recruitment).
この温泉は通年営業しているため、いつでも入浴できる。
This hot spring operates year-round, so you can bathe there anytime.
通年採用を行っている会社が増えている。
More companies are carrying out year-round recruitment.
この野菜は通年を通して手に入りにくい。
This vegetable is hard to obtain throughout the year.