Cal. Sts. & High. Code § 8686

If it appears to the legislative body that, according to the dates when taxes are collected in the city, there will be an insufficient amount on hand to pay the interest when due, according to the method of collection provided by the preceding provisions of this division, the legislative body may direct that such interest or some portion of it be collected in the year preceding that in which the same would otherwise be collected, and thereupon such interest or portion thereof shall be extended on the rolls for such preceding year and be due and collected therein.