During every election cycle, election administrators validate voter registration applications submitted at different times and through various sources, with a notable peak in the demand for voter registration as Election Day approaches. The process of registering to vote, however, is error-prone and may depend on the voter's capacity to fill a form correctly, or the election administrator's capacity to successfully process applications as the voter registration window closes. Such errors can limit a prospective, and eligible, voter's ability to cast a valid ballot. This study assesses the impact of time and registration source on the rates of rejected voter registration applications by analyzing monthly county-level voter registration reports during the 2012 election cycle in Florida. I find that there is a dynamic relationship between administrative and seasonal factors at the county level, which condition the rates of rejected voter registrations as the registration deadline approaches. These findings suggest complications in not only the process of registering to vote that may stem from differences in voter engagement but also the variation in administrative oversight throughout the election cycle.