Did you store them in the fridge for any length of time first?

No, I didn't. Don't know about the O.P. It was cold here though before they fell.

I did not store them in the fridge. Collected them about a month ago. We had one cool front, but no weather below 45 to speak of!

I have been growing trees from seed for 4 years now and what I do see are some very staggered germination times - pines, elm, lime have all germinated over a period of several months...and also, very fresh seeds such as black poplar can germinate immediately for a really brief period (only a week or so) then go into a deep dormancy...and this is really true of numerous perennials...so, I guess I am saying that plants will always hedge their bets, seemingly sacrificng a number of seeds if conditions are favourable. Obviously, I am still a novice at this game but I have become more dubious about hard and fast rules since life is very...tenacious.

Yes, nature makes rules to break them, grin. I had some western red cedar, T. plicata, and the same flat of seeds came up for 3 years.

I have seen Post Oak that are 1-3' tall in the wild that keep leaves all winter (through freezes) and survive no problem. I wonder if these little Red Oak will survive or if I should cover them when the temps dip? Due to the 70's we had Christmas week, I also have about 20 Quercus Polymorpha, and another 5 Quercus Fusiformis that have sprouted as well. Looking to see if anyone has had experience with any Quercus (white or red) surviving winter, and to what extreme. Happy New Year to all!