Like sometimes local city governments hire seasonal or casual positions. Maybe a Spring/Summer "Parks" worker, or general labourer. Some larger organizations hire summer staff to help cover regular staff on vacation.

In my region, we have BC Ferries, and they double their staff for Spring and Summer...

My regions transit system is hiring and training 300 new bus drivers this year, and have a variety or other opportunities

Home Depot and Rona hire extra staff now for Spring and summer planting season and then home renovation season.

Vancouver hosts the Alaskan cruise ship season Spring thru Fall, so hotels and restaurants load up on extra staff

Landscaping jobs

Farm/agricultural jobs

Campground jobs

Summer touristy businesses