California’s citrus season is a nearly year-long cycle of staggered harvests. This sustained availability is possible due to the state’s diverse microclimates and the cultivation of multiple citrus varieties with different ripening schedules. California dominates the domestic market for fresh-market citrus, supplying over 80% of the nation’s fresh fruit. The mild, Mediterranean climate, characterized by warm, dry summers and cool, wet winters, provides ideal conditions for high-quality fruit development.
Peak Winter Citrus Varieties and Timing
The most recognized “citrus season” occurs during the winter months, running from November through March. This period is defined by the harvest of Washington Navel oranges and various easy-to-peel Mandarin varieties. Navel oranges, which are seedless and known for their deep orange color and sweetness, are picked from December until April, making them the quintessential winter eating orange.
The earliest mandarins, such as the Satsuma, often begin their harvest around Thanksgiving in November. Other popular types, including Clementines and Tango mandarins, follow closely, with peak availability spanning December through March. Specialty oranges like the Cara Cara Navel, noted for its pink-red interior and lower acidity, and blood oranges, prized for their crimson flesh and unique flavor profile, become available starting in December or mid-January. These winter varieties thrive in the cool nighttime temperatures necessary for the fruit rind to fully develop its bright color.
Year-Round and Summer Citrus Availability
While winter is the peak season, California’s citrus production extends into the warmer months. The primary summer orange is the Valencia, harvested from April through October and favored for its abundant, high-quality juice. Valencia oranges mature during the summer heat; though their rinds may “re-green,” this cosmetic effect does not affect the interior quality or flavor.
Lemons represent the most consistent year-round production in California, with several flushes of harvest. Varieties like Eureka lemons are nearly everbearing, though their peak volume is seen during the late winter and spring. Grapefruit also contributes to the supply, with harvest beginning in late winter and continuing through the spring and into the summer months, usually from May to September.
Geographic Factors and Optimal Harvest Time
The precise timing of the citrus harvest depends on regional geography and localized climate conditions within California. The majority of the state’s commercial citrus acreage is concentrated in the Central Valley, specifically in counties like Fresno, Kern, and Tulare, as well as in certain Southern California regions. Microclimates in these areas cause slight variations in ripening dates.
For instance, interior valleys experience greater temperature extremes with hotter days and colder nights, causing fruit to ripen a few weeks earlier than coastal areas. Citrus is picked when the internal sugar-acid ratio reaches an optimal level, determined by taste, not just rind color. The fruit continues to sweeten and hold its quality the longer it remains hanging on the tree, allowing for a flexible harvest window adjusted based on market demand and weather patterns.