I agree on the seasonal just being a limiter on straight monthly and not necessarily the use case you are describing. If you did want to try and make it work with just one membership, you can always setup multiple recurring services that are tied to the sale of the 1 membership. I could see setting up 4 Seasonal Recurring services for the busy season and just selecting the busy season months and then 2 seasonal Recurring Services for the slow season. This though would put all 4 Recurring Services for the busy month due on the same day, so you would have to adjust.
Additionally, I am not sure what months or how long your busy season is but you could always modify the membership at the start of the month to have a set number of recurring visits depending on what time of the year the membership was sold. For example, if your busy season is June, July, and August, on July 1st you could modify your memberships recurring service to be weekly for 8 weeks and a second one to be biweekly for the rest of the year.
Not sure if your memberships expire and need to be renewed but you could always just sell it with bi-weekly recurring service attached and then when a membership is sold, add an additionally bi-weekly recurring service to that location for the summer dates you want to go every week. This will require adjusting every membership but most companies check every membership anyways to make sure it was sold correctly and there is a payment method on file, so this may be the least manual work of all of these work around suggestions.
Hope this gives some food for thought and let us know what you end up doing but probably better than selling the customer customer 2 separate memberships.
Element Mist
