Depends on which sort of begonias - some of them should have been lifted already - see the RHS webpage https://www.rhs.org.uk/advice/profile?pid=815 - it may be mild today but that's no guarantee that it won't be -10 degrees with a foot of snow by the weekend.

Hi, I agree with Urbanite, only B semperflorens, and tuberhybrida groups are used for summer bedding, and will be killed off by frost, the semperflorens can be potted up and grown as houseplants if you wish, tuberhybrida should be lifted and stored frost free over winter, and started off again in pots, in a greenhouse next spring, Derek.

Just one of mine just about survived right through to early spring for the first time ever but died at the last minute.
Unless this winter is even milder than last they won't survive but if they did, yes they would keep on flowering the following year.

Hya Thank you very much for your advice, its being most helpfull, I will lift some of them just to be on the safe side and put them in the Greenhouse, they are the ordinary Bedding Plant as you mentioned, and you usually never last this long, I think the Begonia's are Beautifull, and always looking for advice on growing them, I shall get the ones that you can lift and store till next season, as you mentioned, so Thanking you once again, and have o Merry Christmas, to you all,

The tuberous rooted ones that you lift and store are very different from the little bedding ones though, and usually used in containers rather than for bedding. You can also get trailing ones for hanging baskets.