Mich. Comp. Laws § 8.6: Statutes and rules; time; computation.

Sec. 6.

This section applies to the statutes and administrative rules. In computing a period of days, the first day is excluded and the last day is included. If the last day of any period or a fixed or final day is a Saturday, Sunday or legal holiday, the period or day is extended to include the next day which is not a Saturday, Sunday or legal holiday.