noun
high season; peak season
Borrowed from English; used for the busiest or most popular time for tourism, business, or events.
夏は観光のハイシーズンです。
Summer is the high season for tourism.
ハイシーズンはホテルの料金が高くなる。
Hotel rates go up during peak season.
Variant with a middle dot, sometimes seen in dictionaries or careful writing.
Loanword from English 'high season'.