Wyo. Stat. Ann. § 31-2-407

Every certificate and number issued pursuant to W.S. 31-2-401 through 31-2-409 shall be valid from July 1 of the year designated until June 30 of the following year. The use of license plates or decals issued during any registration year is hereby authorized and legalized until and including the first day of August of the next succeeding registration year.