旺季 (wàng jì): busy season; peak period; see also 淡季[dan4 ji4]

Every summer vacation is the busy season for our travel agency; we're so busy we don't even have time to eat.

Before the Spring Festival is the peak season for train ticket sales; many people start lining up in the early morning to buy tickets.

The busy season for this restaurant is winter, because everyone loves to eat piping hot hot pot.

During peak tourist season, hotel prices by the beach can triple, and it's very hard to book a room.

In order to cope with the peak sales season, the factory hired fifty temporary workers in advance.

The busy season for e-commerce platforms usually starts in November and lasts until the end of the year.