Temperatures are predicted to drop into the 20's over the next couple nights in some production regions

Dr. Jim Schupp of Penn State offers guidelines for evaluating exposed fruit and handling frozen fruit.  The freezing point will vary between varieties and maturity but in general apples begin to freeze at 28.5 to 28 degrees Fahrenheit.
In general, the lower the temperature and the longer the exposure, the greater the damage. Recovery of fruit is dependent on duration and temperature and on the rate of thawing. Slow thawing is beneficial for preserving fruit tissue integrity.
Do not handle fruit until thawed. This requires patience but it is a critical step is salvaging your crop.

Frozen or not? Jab your thumbnail through the skin and into the fruit. It it pops and is juicy, not frozen or the fruit is sufficiently thawed. If it doesn't pop with juice but feels like you are sticking your finger into a popsicle, the fruit is still frozen. 
Storage and marketing issues need to reslved with fruit hat has been exposed to temperatures below 29 degrees for more than a brief time. Evaluate and sample fruit throughout the process. 
As Jim says, your first loss is your best loss. 
 
Read more in the article below. 
https://extension.psu.edu/fruit-harvest-handling-of-frozen-apples