Players had warmed up for the clash at Villarreal's Estadio de la Ceramica and some fans entered the stadium before the decision was taken because of the alert in the Castellon region among other areas on the east coast.
Villarreal said in a statement the match had been postponed because of "the safety recommendations due to the risk of flooding".
La Liga said a new date and time for the match would be announced as soon as possible.
In October the Valencia region was hit by devastating flash floods which killed over 200 people as well as wrecking homes and cars.
