I generally cycle down to about 14 degrees or so. A fleece neck gaiter has been the best solution for me. Mine is North Face brand, bought at a thrift shop some time ago.

It opens wider at the neck, and has an elastic drawstring thingy around the top, which easily fits over or under the nose.

There is plenty of room for my pointy irish chin and my big mouth. The roominess moderates the condensation factor, and the plain fleece breathes well enough so that it does not reduce my O2 intake.

At 32 degrees, it goes around my neck, a little colder, it sits up on my chin, and moves up as it gets colder, without needing adjustment to the elastic.