LOS ANGELES — Some normally warm California spots shivered Sunday as early-morning temperatures plunged, leaving even polar bears at the San Diego Zoo seeking shelter. But growers in the Central Valley were relieved to learn most orange and lemon crops probably avoided significant damage despite temperatures in the high 20s.

‘‘We were just a little bit colder, by a degree or two,’’ said spokesman Paul Story of California Citrus Mutual, a growers’ trade association. ‘‘For the navel oranges, that’s not cold enough to do a measurable amount of damage.’’