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Author Topic: Winter cluster core temps - 68-70 Degrees F!  (Read 1369 times)

Offline tjc1

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Winter cluster core temps - 68-70 Degrees F!
« on: February 08, 2018, 04:39:43 pm »
Ken Warchol, a Mass state bee inspector, recently spoke to our club on a variety of topics around winter and spring in the bee yard. One bit of info that surprised me was his finding (during a USDA sponsored study he ran recently, using $3000 hives rigged to monitor weight, humidity, temperature and more) that the broodless winter cluster ran at a nominal internal temperature of 68 to 70 degrees F, down to 58-60 degrees when the temps went below zero. I had always thought that the core of the cluster was kept at a constant ca 93 degrees. He says that you can watch the temp start to rise around the end of January (here in MA) over the course of a week and a half, to 92 degrees when brood rearing begins. The talk was recorded - comments about cluster temps run from about 6:50 to 7:50 and then 9:40 to 10:10.

https://www.youtube.com/watch?time_continue=612&v=s1r-nC9tOn8

Offline bwallace23350

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Re: Winter cluster core temps - 68-70 Degrees F!
« Reply #1 on: February 08, 2018, 05:58:42 pm »
Interesting stuff.

Offline Michael Bush

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Re: Winter cluster core temps - 68-70 Degrees F!
« Reply #2 on: February 08, 2018, 07:12:07 pm »
It's only 93 F when they are rearing brood, which sometimes they do.  When you have an observation hive you can feel the difference with your hand on the glass when they are rearing brood and not rearing brood.  The difference is quite dramatic.
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Offline beepro

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Re: Winter cluster core temps - 68-70 Degrees F!
« Reply #3 on: February 11, 2018, 09:29:24 pm »
When it is too cold outside the heater bees will start warming up the cluster.  I can
feel their heat while opening their hives during the 50F winter days.  It is what they like
to regulate the temp. to be often in the 70-80s without broods.