Reference: http://www.alfawzan.af.org.sa/node/15982
Question: When does [the legislated time for] the bath of the day of jumu’ah begin; does it begin [after maghrib] the previous night, or after the fajr prayer, or [is it] after sunrise?
Response: The [legislated time for the] bath of the day of jumu’ah begins from [the time of] fajr until sunset. However, [doing so] before going for the jumu’ah prayer is best.