Windmill palm tree cold tolerance?

I currently live in New Jersey plant hardiness zone 6b/7a. I plan on covering and protecting my windmill palm trees in the next couple weeks, preferably the last week of december. However, we are forecasted to have a low of 14 degrees and a high of only 24 tomorrow and 25 the next day. Will the palm trees be able to be unprotected for this extent of time? They were just planted this September.