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Hive temperature vs humidity

Back in November, Bill Reynolds of Viking, Minnesota began monitoring the inside of his beehives for temperature. He purchased an inexpensive desktop weather forecasting station with three remote wireless sensors for his project, and he used a fourth sensor to monitor the ambient outside air. The data for the first weeks can be found in the post, “How do honey bees keep their hive warm?

Originally, Bill set up three hives, each with three deeps and a quilt box. One hive contained a colony of Carniolans, one a colony of mutts, and one was empty. The hives were not wrapped, but all three were placed on the south side of a house with a straw-bale wall blocking northwest winds.

On November 22, Bill wrapped the second hive—the one containing the mutts—with 15-pound tarpaper. Then on November 28, he added a humidity sensor to both occupied hives and began to record humidity as well as temperature. Roughly one month later, on December 24, he removed the tarpaper wrap from Hive #2.

Below are some observations Bill made about the experiment, followed by the actual data:

  1. When comparing the data from the two occupied hives, the tarpaper wrap didn’t have much of an effect.
  2. When wrapping and unwrapping, the temperature spiked inside Hive #2. Presumably, this spike was caused by increased bee activity due to human disturbance. Bill writes, “I am surprised that such little interference outside would cause such a large effect inside.”
  3. The outside humidity levels were very high, at one point 99%, but there was no snow. As the outside humidity rose and fell, the internal humidity of Hive #2 followed closely, as did the readings from the empty hive. On the other hand, the humidity of Hive #1 fluctuated much less.
  4. Coincidentally, the outside humidity dropped just after the wrap was removed.

The first graph below goes back to November 1 and continues through December 26. It is easy to see that in the occupied hives, the internal temperature fluctuated with the outside temperature (black bars) but was consistently warmer. The empty hive temperature remained consistent with the outside air. As mentioned above, the temperature of Hive #2 (blue) spiked when the tarpaper wrap was added and again when it was removed.

Bill-Reynolds-dectemp_27_14

The second graph shows both temperature (dotted lines) and humidity (solid lines). The outside humidity (green line) fluctuates with outside temperature (black bars). For the most part, the Hive #2 humidity (magenta) followed the outside humidity (green), but Hive #1 (blue) was drier on the humid days and wetter on the dry days than the outside. In other words, have Hive #1 was able to minimize humidity fluctuations.

Bill-Reynolds-jan_humidity_2015

If you have any questions, please leave a comment and I will let Bill answer them for you. In the meantime, Bill, thanks so much for this fascinating peek inside your hives.

You can purchase the ambient weather station here: *Ambient Weather WS-10 Wireless Indoor/Outdoor 8-Channel Thermo-Hygrometer with Three Remote Sensors

Rusty
HoneyBeeSuite

*This post contains an affiliate link.

Comments

harold meinster
Reply

On Long Island, NY the weather has been relatively warm. The humidity inside the hive was high with water vapor inside the inner cover.

I took off the tar paper and opened all the entrances to full open for ventilation. Christmas day it was in the 60’s and the bees were out. Today it was 57. Next week its going to be cold, below 30 and then I will reduce the entrances.

I keep a reading of the inside temp and one box is very warm. That hive is full of bees and the temperature changes are confusing them.

Sometimes its best to let them handle the hive naturally instead of micro managing.

shawn
Reply

Very interesting. In Dennis Murrel’s experiments with winter moisture and condensation he stated noticing a big difference between strong and weak hives. Was there any difference in strength between the two hives?

It’s not uncommon here for people to wrap in tar paper. It’s not for insulation, it’s intended to allow for solar heat gains on sunny days, where another degree or two might allow the cluster to move to a new area of honey in the hive. It might provide the most benefit on sunny days in say February when the days are a little longer and the cluster might be depleting the honey on one side of the hive.

Phillip
Reply

Bill writes, “I am surprised that such little interference outside would cause such a large effect inside.”

Bill’s observations match with mine. When it’s too cold to look inside my hives, I push my ear to the side of each hive to see if I can hear the bees buzzing. If I don’t here anything, I knock on the side of the hive and give another listen and usually hear the roar of the cluster for a few seconds and then I know they’re okay. But some colonies, even with my little “Are you okay?” tap, will wake up in a bad mood and send hundreds of bees pouring out the hive, even when it’s freezing outside. I had no idea it would take the bees so long to calm down, though. The temperature in Bill’s hive seemed to spike for about two weeks after being disturbed. I realize we’re looking at a limited data set here, but these are interesting observations. Perhaps I should invest in a stethoscope or just stop knocking on my hives in the winter.

I’m curious what kind of readings Bill would get from a hive that’s wrapped all winter and one that isn’t. I’m not convinced wrapping does my bees any good because my hives are in a very wet, damp, humid environment. The wrap is soaked most of the time and even turns to ice from time to time.

Rusty
Reply

Phillip,

I’m convinced wrapping only helps if there is lots of sun (i.e. lots of solar heat to collect), otherwise moisture seems to be a bigger problem with wrap than without it.

Eddy
Reply

From the looks of the second graph, I’d say your carnies are doing better than the mutts when it comes to temp and humidity control. Glad to hear it, as I have carnies, and live in the Pacific NW, where humidity can be high all rainy winter long! Still can’t tell if they’ll make it through this winter though, we had honey robbing in the fall :(. And it’s been too cold to get in the hives to check/replace candy boards. Beekeeping, not for the faint of heart!!
-E

Morris
Reply

Hi Rusty and Bill, these are really impressive charts. Rusty can you ask Bill to email me at ostrofsky[at]pacinfo[dot]com? I hope to get jpg versions of the charts. This way I could enlarge them so I can better read them. I would like to show them in my beekeeping classes illustrating the effect of disturbing the colony. Finally, I would like to find out where to purchase the equipment. Thank you, Morris

Rusty
Reply

Bill,

I already sent the .jpgs to Morris, but the questions I left for you.

Robin
Reply

That is really interesting. So basically, the bees in this test were better able to regulate humidity inside the hive that wasn’t wrapped. It would be really interesting to test this on a much larger scale. It makes me kind of glad I didn’t wrap mine this year but put up a wind block instead.

Roger
Reply

I am surprised by the statement that “When comparing the data from the two occupied hives, the tarpaper wrap didn’t have much of an effect.” Before wrapping the two hives were at almost the same temps, but after wrapping the blue line was consistently above the green line, with only a few exceptions (perhaps on overcast days with no solar gain??). Of course, replicates are needed but I would have thought that the wrapping has a reliable effect of helping to maintain slightly higher temps.

Rusty
Reply

Bill, your comments?

Bill
Reply

Morning

Roger – Prior to wrapping Hive 2 (H2), its temp ran about 3-4 degrees colder than Hive 1 (H1). The best I could tell, both clusters were mostly in the bottom deep. After wrapping, for about 24 hours there was a spike in temp for H2 of 10 degrees. Once the spike settled, H2 ran about 6 degrees warmer than H1. So in all, there was a shift of about 10 degrees.

Before removal of the wrap both hives temperatures were within a degree or two. Upon removal of the wrap a 6 degree spike was noticed in H2 for about 24 hours. After the spike settled, the temps between the two hives was again only a few degrees.

So, a few degrees here and there was the reason for the comment “When comparing the data from the two hives, the tar paper wrap didn’t have much of an effect”.

Thanks for the comment and reading the blog!

Bill
Reply

The equipment I am is an Ambient Weather Station with remote wireless sensors.

max
Reply

This is all extremely useful.
I’m in a very different climate – my issue is at times the heat.
Where would I be able to order the equipment?

thanks max ( Queensland, Australia)

Rusty
Reply

Max,

There is a link to the equipment at the end of the post (above) but I don’t know how that would work from Australia.

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