How to tag seasonal access?

There is a park in my city that is free to access in the off-season, but you have to pay to enter in the spring and summer. Is there a way to tag the access to reflect this?

You could do something like this:

fee=yes
fee:condtional=no @ (Sep 23 - Mar 21)

Beginning of spring/fall might be different at your location, certainly different in the southern hemisphere.

you can use conditional also with spring/summer/… etc.
https://wiki.openstreetmap.org/wiki/Conditional_restrictions

Hmm, so perhaps access=customers, access:conditional=yes @ ([some definition of winter]) ?

The problem is that I’m having trouble finding out what the exact dates are that they change over. Some of the paths are also only accessible in the summer, while others are open in the winter and summer, and some (pistes) are winter only. I may have to email the facility to ask about the dates. Luckily I found a map of the paths.

As for fee=* tagging, what elements is this normally added to? Entrances?

you can transfer the value scheme of access:conditional to fee:conditional (eg. fee:conditional = no @ winter
the fee is normaly added to the main object (amenity, tourism, leisure …), not to the entrances

In this case, I am mainly looking to tag paths, so fee=* would not be appropriate. There is additionally no single node or area to tag besides the entrance gates, since this place has some public areas and some areas that require a ticket to access, and the area that represents the facility covers both. (Way: ‪Jardin botanique de Montréal‬ (‪87382664‬) | OpenStreetMap)

For me it would make sense to may map these restricted areas. are there alse barriers like fences?

Yes, and these barriers are mapped. I am looking to retag all the footpaths inside appropriately, since many are also only for employees, and figured that while I am changing all of them, I may as well represent the seasonal access changes if I can.