Lawrence,
I'm a hobby beek and live in Seattle. Many of us do OA vapor treatments in December & January.  We get cold snaps of a week or more during those months when the temps get to freezing or below at night and in the high 30's in the day, but I don't treat when it's that cold.  This year my hives got a treatment  the 2nd week of December at mid-afternoon when the temp was about 45.  The mite drops were in the hundreds.  I treated again in mid-January on a sunny day when the temp was about the same; that time mite drops were under 40.  It's been so warm in the city most of the winter that the bees didn't really cluster; they've been all over the top of their hives (like in summer!) since early December, and I've been feeding them since then.  (Some locales in Puget Sound had a bad summer for nectar and many PSBA members reported their hives didn't put up much honey.)  Two days ago when it was close to 50F, I observed many of the foragers bringing back pollen  - likely early crocus - a good sign that they're brooding up.

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html