It takes time. Once you have those nubs, they are ok.
Definitely cold is not a problem. I have had potatoes
sprouning in the frig.
You can plant them anytime but since it will be cold for the next week or so, just hold on and then plant them.
You can plant potatoes even without greening (pre=sprouting) but it will take longer to sprout in the ground.

Put taters in bag with small holes for ventilation in warm dark utility room (with washer= dryer). sprouts will start to grow in 5 to 8 days. GOOD LUCK Bill

Sprouts grown in the dark is not very good.
The experts recomment placing them single layer on a tray, in the light at room temperatures. This is called "GREENING"
because while sprouting the seeds will get green.
Sprouts grown this way are better than those grown in the dark, in thr bag.