In our relatively cool coastal New England climate I've convinced myself
that painting two adjacent sides of my hive bodies a dark color, and
the other two sides white, works well.  At the earliest spring inspection
(usually in early March around here) I rotate the hive bodies to present
the dark, sunlight absorbing, sides to the south & west.  Later, when the
weather gets consistently warm--in the middle of June--the white sides get
turned to the sun.  With some early feeding of sugar and pollen, this gives
my colonies the boost they need for early splits or two-queen colony
production (my favorite).  Of course, if the management is not careful, you
also can get early swarms!
        Sandy Moss
        [log in to unmask]