Cal. Elec. Code § 9014

(a) A petition for a proposed initiative or referendum measure shall not be circulated for signatures prior to the official summary date.
(b) Subject to subdivision (d), a petition with signatures for a proposed initiative measure shall be filed with the county elections official not later than 180 days from the official summary date, and a county elections official shall not accept a petition for the proposed initiative measure after that period.
(c) Subject to subdivision (d), a petition for a proposed referendum measure shall be filed with the county elections official not later than 90 days from the date the legislative bill was chaptered by the Secretary of State, and a county elections official shall not accept a petition for the proposed referendum measure after that period.
(d) If the last day to file a petition pursuant to subdivision (b) or (c) is a holiday, as defined in Chapter 7 (commencing with Section 6700) of Division 7 of Title 1 of the Government Code, the petition may be filed with the county elections official on the next business day.