When
can temperatures be dangerously cold?
"January
and early February is the coldest time of the season. This is a
really critical time for the monarchs," says Dr. Lincoln Brower.
"We know temperatures below -8°C will kill about 50% of
the monarchs. However, if the butterflies are also WET, it will
kill close to 80-90% of the monarchs."
Graphic
© Dr. Lincoln P. Brower,
Sweet Briar College
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