Beehive Instrumentation Project-6: Winter measurements

November in Palmer, Alaska and a little snow is on the ground.

back yard 11-4-15

It’s been several months, but it’s time to see what hive conditions are like in colder weather.

The RPi2B has the same programming as before to read the HTU21D-F temperature and humidity sensor. I have added a little insulation to the inner cover to (hopefully) inhibit condensation on the underside of the cover. The hive has a partial screened bottom board and an upper entrance cut into the underside of the inner cover frame.  We want to know if the humidity gets high enough to condense water vapor to liquid.  We also want to know if the bottom-to-top air circulation is chilling the hive too much.

RPi & T-H sensor

Here is a sample of the SSH readings for about the last hour:

Pi T-H 11-4-15

Ambient conditions–per a consumer radio weather system are 30.6 degrees F and 82% relative humidity.  So the temperature under the inner cover is quite a lot warmer than outside the hive.  Humidity is lower than ambient, but creeping up gradually.

Per the dew point calculator at,  a temperature of 45 degrees F and a %RH of 74% yields a dew point of 37 degrees F.

dew point

Which suggests that the hive is reasonably safe for temperature and humidity.

A “manual” log for easier comparisons:



HTU21D-F placed under inner cover of hive

Ambient 30.6 deg F 82% RH
1:55 PM AKT
pi@raspberrypi ~ $ python
Temp: 7.52624511719 degrees C
Temp: 45.5665463867 degrees F
Humid: 71.6901245117 % rH

2:00 PM AKT
pi@raspberrypi ~ $ python
Temp: 7.48334472656 degrees C
Temp: 45.4700205078 degrees F
Humid: 73.3914794922 % rH

Ambient 30.0 deg F 82% RH
2:53 PM AKT
pi@raspberrypi ~ $ python
Temp: 7.2044921875 degrees C
Temp: 44.9680859375 degrees F
Humid: 75.7413330078 % rH



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