To create a season that you can use across multiple products see video below:
To add a season in a specific product, navigate to the Availability tab in the product edit interface.
Under the Operating Type field, select either Opening Hours or Fixed Times depending on your operation
Then click on the + Add Season button. (see below)
In the pop up, give the season a name and set the dates the season is valid then click Done.
You can now set the days and hours for this product for that season.