Veh. Code, § 9706

(a) Application for partial year registration in conjunction with an application for original California registration shall be made by the owner within 20 days of the date the vehicle first becomes subject to California registration. Any application for partial year registration submitted after that 20-day period shall be denied registration for a partial year, and the vehicle shall be subject to payment of the fees for the entire registration year. In addition to the fee for the registration year, a penalty, as specified in Section 9554, shall be added to the fee for registration.

(b) Any application to renew registration for a part of the remainder of the registration year or for the entire remainder of the registration year shall be made prior to midnight of the expiration date of the last issued registration certificate. Application shall be made upon presentation of the last issued registration card or of a potential registration issued by the department for use at the time of renewal and by payment of the required partial year fees, or, if renewal is for the remainder of the registration year, by payment of the annual fee required by Section 9400 or 9400.1, as reduced pursuant to Section 9407.

(c) Notwithstanding any other provision of law, an owner who registers a vehicle pursuant to this article during a calendar year shall, if the vehicle was not operated, moved, or left standing upon a highway, file a certificate of nonoperation prior to the date of the first operation of the vehicle on the highways in a manner which requires that registration and shall, by December 31 of each calendar year thereafter, file a certification pursuant to subdivisions (a) and (b) of Section 4604 when the vehicle is not registered for operation on the highways for the succeeding calendar year.

(d) Notwithstanding subdivision (c), the owner of any vehicle being moved or operated for the purpose of providing support to firefighting operations while the vehicle or owner is under contract to the United States Forestry Service, the United States Department of the Interior, the Bureau of Land Management, the Department of Forestry and Fire Protection, or the Office of Emergency Services may obtain partial year registration if application is made within 20 days of the date the vehicle is first operated, moved, or left standing on the highway and the owner has obtained a letter of authorization from the department prior to the date that the vehicle is first operated, moved, or left standing on the highway.