What is the very best exterior cold weather house paint for wood siding? Temperatures in Wisconsin winters can reach -30 degrees where I live.
Devoe Regency is a very good paint. Also an elastomeric coating would work great.
The paint isn't the real problem, any good paint will do a good job. The prep determines how well the paint does. I suspect the caulking will be the real weak link. Use a good urethane sealant as this will do the best with such temperature extremes.
Make sure the prep is done right and very good primer is used.