Thanks for the responses. That does make sense considering I have a Meyer lemon is doing the same thing on the branches that froze also. Does this indeed heal over time? Is there anything I need to do?

I wouldn't know, I've never grown an orange in my life. But my sister, who has, reckons it's stress-related, either via fluctuating temps or an irregular moisture supply, or even both. And there's not much you can do about it except, perhaps, monitor the moisture supply, keeping it regular. I suppose - as with tomatoes, which I do know about - a sudden influx of moisture will expand the fruit's innards, splitting the skin that is unprepared for the expansion. I never knew why my sister told me these things. Now I do. So I can pass them on!

From September through November splitting in navel oranges often occurs in green fruit. It's attributed to the rind not being able to expand when the fruit is filling with moisture and the rinds burst open due to the pressure. Rinds that are sunburned or have lost their elasticity are more apt to split. The number of fruit affected seems to vary from year to year. Fruit on the south or west sides of the tree may be more vulnerable due to sun exposure. Splitting seems to be related to extreme fluctuations in temperature, humidity, soil moisture, and even fertilizer levels. Regular, deep irrigations are a good practice as is using a 3 inch layer of mulch over the root zone. Here's a link to irrigating citrus, fertilizing, etc. http://cals.arizona.edu/maricopa/garden/pubs.htm

Good information, Cori. Citrus splitting can also be a sign of a Calcium deficiency; our custom fertilizer has 2% Calcium.