California Code, Penal Code - PEN § 1533

Upon a showing of good cause, the magistrate may, in his or her discretion, insert a direction in a search warrant that it may be served at any time of the day or night. In the absence of such a direction, the warrant shall be served only between the hours of 7 a.m. and 10 p.m.

When establishing “good cause” under this section, the magistrate shall consider the safety of the peace officers serving the warrant and the safety of the public as a valid basis for nighttime endorsements.