The maximum duration of a standard residential lease in Wisconsin is one (1) year. Leases for longer than one year must be in writing and signed by the landlord and tenant (WI Stat § 704.03(1)).
Oral leases are valid for shorter durations, but it is recommended that all lease agreements be in writing for greater legal protections.
In addition, if a lease longer than one year is not in writing, the tenancy is assumed to be on a month-to-month basis (WI Stat § 704.03(2)).
The information for this answer was found on our Wisconsin Residential Lease Agreement answers.