Hi:
 
Moisture is a problem most everywhere.  We notice a big difference
during the growing season in Seattle, WA or Aberdeen, MD compared to
western Montana, which is more humid than eastern MT or WA.
 
In the winter, the inside of the hive can get really wet in the coastal
locations.  But even in Montana, confined hives condense a lot of
moisture.  Have you ever tried camping overnight in a tent that doesn't
"breathe?".
 
We generally use some type of inner cover or top entrance to provide some
head room and a bit of ventilation.  We narrow down the bottom entrances
to keep out mice and stop the wind.
.
One of our problems is wind.  A stiff breeze causes a wind chill that even
the bees have trouble handling, so we try to avoid the chimney effect.  A
bit of dark roofing felt around the hive or at least on top may help warm
the inside a bit on sunny days (a rarity in Missoula in the winter).  This
could be wishful thinking, but most of our beekeepers think it helps the
cluster break and move on a sunny day.
 
Very few of our folks use insulation under the cover.  Years ago, some
packed in straw but found that during the January thaw and February freeze
cycle, the straw turned into a block of ice.
 
We do pull our hives together so that one shields the other from the wind.
Often the whole group gets a single wrap - but not too tight or the
moisture builds up too much.
 
Where we get lots of snow, the hives are buried most of the winter.  I
wonder whether insulation does any good for hives packed in nature's
igloo.
 
Maybe Allen can tell us if anyone has ever measured core temperatures in
colonies with and without the insulating pillows?
 
Anyway, white Christmas in Missoula.  We had 28" since Thanksgiving, got
14" over Christmas day, and it is still coming down.  Cross-country skiers
and folks with sleds out all over town and on the campus.  Just saw a
family ski by my office window.  Mild temperatures (about 10 degrees F).
Highways and main streets have had at least a single pass with the
snowplow.  On the side streets, you had better be driving something with
ground clearance.
 
Despite commonly held opinions, this is a bit more snow than we usually
get in Western Montana.  Fairly common in central or eastern parts of the
state.  Hardly worth comment by our northern friends.
 
Best Wishes for the Holidays and New Year.
 
Jerry Bromenshenk
The University of Montana-Missoula
[log in to unmask]
http://grizzly.umt.edu/biology/bees