Re: reducing the hive entrance (thanks @Dawn_SD and @Peter48), I made a reducer to get the entrance down to 3 inches (about 8 cm) out of some spare cedar, with a thin backstop made from a paint stirrer as the cedar is not high enough to completely fill the entrance, glued together, with two nails to go between the slots of the bottom metal screen to hold it in place. Then I realized this would be permanent, as I’d have to remove all of the frames to take it out. And the bees might cement it in.
My question is: is 3" a good year-round opening size? Or, do I need to have the reducer be replaceable so I can vary the entrance over time? I read these threads (1, 2) which suggest 15 cm (6 inches) as a size bees seem to prefer, but no qualification was made based on local climate.
Here is my local temp range (the red and blue lines are F):
My hive will not be in full sun all day, maybe 70% of the day.
Here is my entrance reducer:
If I need to vary the entrance over time, I’ll probably just cut another piece of cedar and screw it to the front of the hive, standing vertically.