The California Rare Fruit Growers web site says, the Carambola can tolerate temperatures as low as 27° F for short periods of time. Well, mine lives up to its sub-tropical categorization: Despite several nights of 40 degrees F temperature, my carambola trees are still happy, and producing their second crop. The fruits are getting sweeter by the day, ripening on the tree. There is some cold damage (not easily seen in this photo) where the fruit's skin has turned brown, but the inside's still tasty!
Here in Central Florida, my carambola trees are evergreen.
The carambola fruit, i.e. Star Fruit, is crunchy like an apple, yet juicy and sweet (although some cultivars are not sweet, and are cooked . When cut, its cross section resembles a 5 (sometimes 6) pointed star. One thing I like about the skin of the carambola, is that it is naturally waxy, making it quite easy to use a soap and water solution to clean any black sooty mold that arises.
One final thing to mention: if you see small pinhole markings on the fruit, it may be caused by stink bug's piercing-sucking mouth parts. The fruit should not have anything wrong with it, but if you see any small area rotting, just discard it and enjoy the rest.
More information on carambolas can be found here