i've planted garlic here the day before the ground froze and it did ok. it does depend upon what type of garlic you have and such, but if the garlic otherwise will do ok in your area and soils it should be ok. it may not be optimal, but i think it will be ok.
p.s. green garlic is an easy crop.
I have planted garlic in December, in frozen ground using a pick to whack out a hole to drop the clove in and then stomping the frozen soil chunk back over it. Brutal I know, but it grew just fine and I got a good harvest. I don't recommend this method, but sometimes if you procrastinate long enough you turn into a mad scientist.
I planted a little garlic a week or so ago - guess I need to check on it eventually and see if it's sprouted. How long does it take?