I think they need to be stored cold, but frost-free, if you don't leave them in the ground - which I don't as I find slugs spoil them.
I put them in paper bags in the fridge salad drawer in summer, if I have excess (we have a second fridge in the utility room for veg, seeds, and alcohol!) The maincrop goes in the shed in a dustbin with spent compost to keep them moist. They keep through to the spring like that before sprouting.