Cal. Gov. Code § 11020

(a) Unless otherwise provided by law, all offices of every state agency shall be kept open for the transaction of business from 8 a.m. until 5 p.m. of each day from Monday to Friday, inclusive, other than legal holidays, but the office of Treasurer shall close one hour earlier. However, any state agency or division, branch or office thereof may be kept open for the transaction of business on other hours and on other days than those specified in this subdivision.

(b) If the provisions of this section are in conflict with the provisions of a memorandum of understanding reached pursuant to Chapter 12 (commencing with Section 3560) of Division 4 of Title 1, the memorandum of understanding shall be controlling without further legislative action, except that if the provisions of a memorandum of understanding require the expenditure of funds, the provisions shall not become effective unless approved by the Legislature in the annual Budget Act.