Dave Whittinger in Jacksonville, TX is familiar with vermiculture. I think winters there might generally be slightly warmer than yours, but maybe not.
Here's a post he did several years ago
https://garden.org/thread/view... and I seem to recall a YouTube video he did, but my memory may be faulty on that. He may still have one going. I'm going to flag him. His post, along with several others on the subject, are in the Soil and Compost forum. There was some discussion of winter temps, but I'm not sure whether a minimum was established or not.
@dave