Excerpted from Rotary International Bylaws:

14.010. Selection of a Governor-nominee.
The district shall select a nominee for governor not more than 36 months, but not less than 24 months, prior to the day of taking office.  The nominee shall assume the title of governor-nominee-designate upon selection and shall assume the title of governor-nominee on 1 July two years prior to assuming office as governor.  The board shall have the authority to extend the date under this section for good and sufficient reason.  The nominee will be elected at the RI convention held immediately preceding the year in which such nominee is to be trained at the international assembly.  Nominees so elected shall serve a one-year term as governor-elect and assume office on 1 July in the calendar year following election.
14.020.1. Method of Selection of Governor-Nominee.
Except for those districts in RIBI, a district shall select its governor-nominee either by a nominating committee procedure as hereinafter provided or by a ballot-by-mail as provided in sections 14.030. and 14.040. or, alternatively, at the district conference as provided in subsection 14.020.13., the choice of which shall be decided by a resolution adopted at a district conference by a majority of the votes of the electors of the clubs present and voting.
14.020.2. Nominating Committee for Governor.
In districts adopting a nominating committee procedure for selection of governor-nominee, the nominating committee for governor shall be charged with the duty to seek out and propose the best available candidate for governor-nominee.  The terms of reference of the committee, including the method for selecting members, shall be determined in a resolution adopted by the electors of the clubs present and voting at a district conference.  Such terms of reference may not be inconsistent with the bylaws.
14.020.4. Suggestions by Clubs for Governor.
In a district selecting its governor-nominee either by nominating committee procedure or at the district conference, the governor shall invite the clubs to submit their suggestions for nominations for governor.  Where the nominating committee procedure is to be utilized, such suggestions shall be considered by the nominating committee so long as they reach the committee by the date established and announced by the governor.  Such announcement shall be made to the clubs in the district at least two months before such suggestions must reach the nominating committee.  The announcement shall include the address to which suggestions shall be sent.  The suggestions shall be submitted in the form of a resolution adopted at a regular meeting of the club naming the suggested candidate.  The resolution shall be certified by the club secretary.  A club may suggest only one of its own members as a candidate for governor-nominee.
14.020.5. Nomination by Committee of Best Qualified Rotarian.
The nominating committee for governor shall not be limited in its selection to those names submitted by clubs in the district.  The committee shall nominate the best qualified Rotarian who is available to serve as governor.
14.020.6. Notification of Nomination.
The chair of the nominating committee shall notify the governor of the candidate selected within 24 hours of the adjournment of the nominating committee.  The governor shall then publish to the clubs of the district the name and club of the nominee within 72 hours from receipt of the notice from the chair of the nominating committee.  Publication of the announcement consists of a written notice by the governor by letter, e-mail or facsimile to the clubs in the district.

Excerpted from District Policy and Procedures:

Article 1
In July, the District Governor shall advise the presidents of all clubs in the District that they may propose a
candidate for consideration by the Nominating Committee, for selection as a nominee to serve as District
Governor for the Rotary year three (3) years hence. All proposals must be submitted to the District Governor on
or before 1 October on fully executed forms available from the Governor and on the District website.

Article 2
The Nominating Committee shall review all the submissions, select the best-qualified candidate and the
Governor shall then publish to all clubs in the district the name and club of the nominee.

Article 3
In the event a club wishes to propose a challenging candidate for Governor-nominee the procedure for proposal,
concurrence and subsequent ballot-by-mail shall be in strict accordance with the applicable RI Bylaws. (14,
14.020.8 and 14.020.11).

Article 4
In the absence of a challenging candidate, the Governor shall declare to all clubs in the district that the
candidate of the District Nominating Committee is the Governor-nominee. The Governor shall certify the name
of the Governor-Nominee to the RI General Secretary and the presidents of the clubs within fifteen days after
such declaration.

Article 5
In the event that a District Governor-Nominee finds it impossible to assume the duties as District Governor or
moves into the District Governor-Elect position early, the District Governor shall issue an invitation to all clubs
in the district inviting proposals for a District Governor-Nominee. All proposals shall be reviewed by the
Nominating Committee.