Cal. Commercial Code § 2723

(1) If an action based on anticipatory repudiation comes to trial before the time for performance with respect to some or all of the goods, any damages based on market price (Section 2708 or Section 2713) shall be determined according to the price of such goods prevailing at the time when the aggrieved party learned of the repudiation. (2) If evidence of a price prevailing at the times or places described in this division is not readily available the price prevailing within any reasonable time before or after the time described or at any other place which in commercial judgment or under usage of trade would serve as a reasonable substitute for the one described may be used, making any proper allowance for the cost of transporting the goods to or from such other place. (3) Evidence of a relevant price prevailing at a time or place other than the one described in this division offered by one party is not admissible unless and until he has given the other party such notice as the court finds sufficient to prevent unfair surprise.