Today was a cold but nice clear sunshine fall day here so I did not check the weather forecast earlier and now I found that it is going down to -7C (approx 20F). It is past mid-night here and I feel tired now, it is cold, the backyard bulb is fused and I may have many other excuses not to venture out and bring inside some of my plants left out in the open.
Please say they will be OK and I feel they will be OK then because it will only be a few hours. I promise to treat them good in the future.
(The breba only 'Desert Kings' have already been cosily protected inside)

The damage will depend on how large the trees and how dormant they already are. 

They had dropped the leaves a week ago and have been through a frost or two. That should have given them sometime to be dormant enough. I guess.

I have a few plants I am worried about as they had not fully hardened off yet and had not dropped any leaves.

Hi Akram,

Its too late to tell you to shelter the plants now thats its morning.
But i would today bring them into wherever you store them for season.

As you probably know already the young plants were most vulnerable from last evening.

In spring if any plant appears dead dont discard as i have had a plant dead to soil level that had 1 main trunk about diameter as a cigar that was dried out completly and shot out growth from under soil late when summer arrived .
I was going to use container for something else until i saw this growth.

Edit: Nelson if mine i would bring into storage. Personally i never let leaves give me any indication of when to bring in. My younger plants hold there leaves much longer than my adult plants which have gone through there cycle growing figs and getting them ripened and energy is spent as they sense the onset of less light and the much cooler temps, the younger ones have yet to go thru this type of cycle and want to continue on growing . Kinda like a juvenile outdoors in cold dont know when to come in but when finally do they realize there cold as heck.