Oranges (citrus x sinensis) are harvested in Florida during all months of the year except July and August. They thrive in the warmer weather of U.S. Department of Agriculture hardiness zones 1 through 9, where temperatures do not often fall below freezing. Florida grows more oranges than any other state, and is second in the world to Brazil in orange production. The many orange varieties come to harvest as early, mid and late season crops.
October to January is early season for orange harvest . Among the varieties available are the cold-tolerant, sweet 'Hamlin' and the medium-sized orange with a pebbly peel called 'Parson Brown.' 'Hamlin' is also considered an excellent juice orange. The well-known 'Navel' and 'Red Navel' are also early season variety oranges. Thick-skinned navel oranges peel very easily and are grown as an eating variety rather than a juicing variety.
Mary King of the Sarasota County Extension says, "Select oranges that are firm and thin-skinned. The best way to judge an orange is by weight in relation to size. Heaviness is a clue to juicy fruit."
The southern portion of Florida is the most active orange-growing area, with orchards extending from the Atlantic to the Gulf coast counties. December to March is considered mid-season in the Florida citrus harvest, with varieties such as 'Sunstar' and 'Gardner' ready to pick. 'Sanjuinelli' is a blood orange variety that is oblong with medium-thick skin and strawberry red flesh. It is considered the sweetest-tasting blood orange. All varieties of orange trees produce few fruit in their first three years and are ready for harvest production after that time.
Valencia oranges are thin-skinned, medium large and very juicy. Valencias account for fifty percent of Florida's orange crop as they come to harvest from March through June and are a popular variety for the home garden. All oranges ripen on the tree and do not improve in flavor after picked. are at peak fruit production when they are 10 to 14 years old, but will continue to give fruit until they reach 20 to 25 years
According to Sunkist growers, "Oranges may occasionally 'regreen' in warm weather. When the fruit ripens on the tree, it turns a bright orange color, as usual. But the warm temperatures of the season may make the skin reabsorb chlorophyll as it hangs on the tree, causing a ripe orange to look partly green."