opening of the beachgoing season
Refers to the official start of the summer beach season, often marked by a ceremony or event. Typically used in news and travel contexts.
The beach season opens on July 1st this year.
On the day of the beach opening, a Shinto ritual is held to pray for safety.
Compound of 海 (umi, 'sea') and 開き (hiraki, 'opening'), from the verb 開く (hiraku).