There is no dedicated Summer Sanction Fee.
For bowlers who want to join a short season league typically offered during the summer months, the option is called a "Basic Membership". The fee is $10.00 and it's good for one league that will bowl 16 weeks or less. The Basic Membership does record the bowlers average for use in local or national sanctioned events!
For complete details and FAQs about the Basic Membership please follow the links below.
USBC Basic Membership Details
USBC Basic Membership FAQ