Wis. Stat. § 16.45

In each regular session of the legislature, the governor shall deliver the budget message to the 2 houses in joint session assembled. Unless a later date is requested by the governor and approved by the legislature in the form of a joint resolution, the budget message shall be delivered on or before the last Tuesday in January of the odd-numbered year. With the message the governor shall transmit to the legislature, as provided in ss. 16.46 and 16.47 , the biennial state budget report and the executive budget bill or bills together with suggestions for the best methods for raising the needed revenues.