They'll be fine. They are extremely tough and as long as they have not been very wet and rotted - and they cope well with wet - they are very likely to be ready to grow again this year. They will also multiply quite fast, so if you leave them in the pots you'll have to make sure that they do not become so crowded that they do not flower. If you put them in the ground, they will be good value in that they look good and they fill a space quite quickly - but you could end up having to dig up unwanted corms fairly often.
Just a thought you could put the pots somewhere sheltered
I've now scared myself. I live in south wales where it does not get as cold as further north and east. They do fine left in the ground all winter and multiply well, mystifyingly coming up a couple of feet from the rest of the clump. Colder climates are supposed to dig them up and protect them.
I planted a supermarket packetful in the veg garden about 8 years ago and I get flowers every year, even though it's regularly -7°-10° in the winter.
So you feel the same as me about their toughness, Busy-Lizzie. That's a relief! I'm not completely off-the-wall, then.
I had some gladioli in troughs last year, came up well and performed well. I left them in the ground over winter. Had to replant one of the troughs a few weeks ago as it had spilt in the cold weather and low and behold, the gladi bulbs were enourmous (compared to planting size - almost trippled in size) and very firm, golden outer skin. they looked beautiful. needless to say, I repotted them in a new trough and looking forward to seeing what they do this year.
It wont hurt them if you bring them in the greenhouse for a few weeks while the weather is colder (where are you?). I have left mine where they are due to the fact that they are planted in amongst other things and too much hastle to bring them in. Plus from my dug up ones, they seem to be handling it quite well outside (warmer down here)