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:
- When comparing the data from the two occupied hives, the tarpaper wrap didn’t have much of an effect.
- 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.”
- 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.
- 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.
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.
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
*This post contains an affiliate link.