My fig plants (in Zone 5a) still have leaves on them; some have green leaves and others have fall yellow colour getting ready to drop. We have forecast of 23F (-5C) on coming Sunday night October 19. The 23F temperature may last for a period of 4 to 5 hours until sunrise. Will I need to take the plants to protected location since they are not in dormancy yet but just getting ready for dormancy? 

Do the plants have figs almost ripe, i had the 1 tree with many almost ripe figs already plump and turning and temps dropped in the 30s and 40s not a freeze though but close so i started to wheel that tree in and out of garage and back out during daytime, most figs did ripen this way but very quickly lost the taste, daily highs were in the low 60s at that point, then following week we had high 70s and even a few days it hit 80 to 84 during day and high 40s and low 50s and figs were still ripening but tasteless for me. This all happened in a 2 week time period. So if your figs are plump and almost ripe by bringing tree in you might get a few that are ok but shortly afterwards might have a flat taste. Hope this help some. By the way as i type this i still have tree getting ripe looking dark figs but no taste . My other mature tree's are void of figs. Hope this helps somewhat from what is my experience this late season.
Martin

Dieseler
None has figs. These are plants rooted last spring. They had good vegetative growth; some had figs that dropped and some did not fruit the first summer of their lives.

What i do is let a good hard frost get to them  around 25 then if temps get warmer at night anything above freezing i leave out just until next frost and then bring in for good, but leaves will yellow and drop either way as happened in years past .
Some years a hard frost of temps in 20s get them and it just stays cold afterwards and they get put in garage right away and lose there leaves in garage. Each year is a little different so i look maybe 5 days ahead for weather temps to help decide when to put away for winter. I also see your plants are a year old only so if it does get that cold like 23 as you think ,  afterwards i would put them away for winter and put something over them to keep any light off them.
Martin

Thanks Martin.
I was looking for this kind of input. It indicates that plant will not suffer damage at 23F and can be left in place to get into dormancy before going into winter storage area. I know I am responsible for the final decision but I appreciate the informative input (from another cold climate).
I wish I could send my plants to a warmer place (Jon's place?!... we just saw the pictures) for winter storage and summer growth and bring them back when they are just on the verge of ripening, just like Radovan once mentioned in one of his posts that he once took one of his plant with ripening figs to his friend's place so he can eat the figs off it and brought the plant back when empty (so generous).

Ottawan, I agree with Martin, and usually don't worry about temperatures in the mid twenties for my mature figs.  But young figs are more sensitive, and it's better to be safe than sorry - especially if they have a lot of green branch tips that haven't "browned up" yet.

If you can take them indoors, or otherwise protect them, jump on it. Why take the risk, and lose a years growth or maybe the whole plant. Unhardened wood will not take near as low a temp as hardened wood.

I had no fig winter damage at a min 20*F in my unheated-garage for the last 2 years.