Special elections to the Iowa State Senate are called by the Governor of Iowa when a vacancy arises within the State Senate. If there is a vacancy in the Iowa General Assembly (i.e., the Iowa state legislature), the vacant seat must be filled by special election. If the vacancy occurs while the General Assembly is in session, the Governor must call within five days of the occurrence of the vacancy for an election as expeditiously as feasible, with a minimum 18-day notice. If the vacancy happens while the General Assembly is out of session, the special election must follow a 45-day notice, as long as the election does not coincide with a school election. All special elections must be held on a Tuesday.