ideally you only have one category per article - otherwise google gets confused- but you can have as many tags as you want to.
so using a summer/winter tag and being able to show the different ones via a selection plugin maybe the way to go

That won’t work for what I want to create. I need all the traffic to the one site. It is a site about a resort and has summer and winter activities

in that case create one site with both the winter and summer activities- people will be looking for summer bits in the winter - to look forward to something.
why limit their options?
all the traffic won't be a problem with a redirection.
but you maybe able to use a plugin to switch off articles - they wil lstill be available in google for a bit so you may need redirections.
it will not create a good user experience.
to me you would allow both summer and winter activities and claerly mark the dates available- or have a banner which is turned on when not available. with a link to the activity that is available.

There are ways of having a way to choose summer/winter in websites which allows all the information to still be available and searchable by google. https://squawalpine.com/ Is a good example

so add a summer winter tag to your articles and restrict the viewing to articles with tag summer or winter
selection can be a switch as in the case of the site , but you can do date range - there are plugins to help with this.
but that sites doesn't appear to work very well- i have winter articles even though i have changed it to summer!
use a filtering to sort your articles - one plugin maybe contentview
but there are other available.
good luck with it.

Thanks for the recommendations

Thank you Loes