Article: Navel oranges bloom in the spring, but the fruit isn't ready until the winter. Start looking for them to ripen beginning in December. They may ripen at any time throughout the winter, though you can harvest the oranges all at once once you see they are ripe. By contrast, Valencia oranges take a full year to grow. They bloom in the spring and grow all through the winter well into the next summer. They will have both a bloom and the fruit in the summer, when you harvest the fruit from last year. When these citrus fruits are ripe, they turn bright orange. While not every variety turns orange all over, most of the fruit will be 1 color. Check your particular variety to see what it should look like when ripe.  For instance, Valencia oranges might still have a bit of green on them, even when they're ripe. Navel oranges, on the other hand, should be all orange. Don't worry about brown spots on the surface of the orange. They just mean your area is particularly sunny or humid. A fully ripe orange will be firm to the touch. If it has soft spots, it's likely overripe and on its way to being moldy. Also, because an orange is juiciest at its peak ripeness, it will feel heavy in your hand when it's ripe. A ripe orange will come off the branch when you give it a light pull and twist. If it's not ripe, it will be much harder to pull off. Leave it on the tree a bit longer if you can't get it to come off easily. If you're still not sure if your fruit is ripe, try cutting one open. Taste it to see if it tastes sweet, like a ripe orange, or bitter, like an unripe orange. While some fruits continue to ripen after you harvest them, oranges do not. Make sure to leave them on the tree until you are sure they are ripe. If the oranges have gone soft or are starting to grow mold, they are overripe.

What is a summary?
Harvest in the winter for navel oranges. Watch for a bright orange color. Check for a firm, smooth fruit that's heavy for its size. Pull and twist on the orange to see if it will come off easily. Perform a taste test on a sample piece of fruit. Let the fruit ripen on the tree.