Wis. Stat. § 20.902
The fiscal year of the state commences on the first day of July in each year and closes on the next succeeding June 30th. All books and accounts of the department of administration and of the state treasurer shall be kept, and all their duties shall be performed with reference to the beginning and ending of the fiscal year. All officers and persons required to render annual accounts to the department of administration and treasurer shall close such accounts on June 30 in each year, and shall render such accounts as soon thereafter as may be practicable, and the fiscal year of all departments, boards and bodies connected with the state government in any manner shall commence and close on the same dates as the fiscal year of the state. A fiscal year ending in an even-numbered calendar year may be designated as an even-numbered fiscal year, and a fiscal year ending in an odd-numbered calendar year may be designated as an odd-numbered fiscal year. For all fiscal purposes the entire summer session of any state educational institution or school under the supervision of the technical college system board shall be considered as occurring in the fiscal year in which such session terminates, and expenditures therefor and revenues thereof shall be charged or credited to the appropriation for such fiscal year. All bills for printing incurred prior to the beginning of such fiscal year for such summer sessions may be paid out of current funds and be replaced at the beginning of such fiscal year.
Wis. Stat. § 20.902