California Code, Government Code - GOV § 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.  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 this section is in conflict with 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 memorandum of understanding requires the expenditure of funds, the memorandum shall not become effective unless approved by the Legislature in the annual Budget Act.

(c) Subdivision (a) shall not apply to any fair or association specified under Division 3 (commencing with Section 3001) of the Food and Agricultural Code.