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Bees in extreme heat

Hi guys, the next week in Perth the temps are between 38 - 40. Is it a good idea to remove the base inspection tray in the bottom of the flow hive to improve air flow?
There seems to be a lot of bearding in hot weather. So much so that that the whole side where the entrance is is covered with bees.
Thanks in advance for suggestions

Hi @Rex,

I use Apimaye screened bottom board which allows to open it completely. Combined with light hive paint and afternoon shade from plants growing next to my hives it gives very good result. At 40°C a “beard” is about palm size area above the entrance.
So, yes, improvement in ventilation helps, but if your hive is a “baking oven” otherwise, this part needs addressing too.

I would leave the tray in place so as to block the air, as well as that I’d close the rear vent. This will allow the bees to efficiently regulate & air condition the hive via the entrance, as long as you have a strong population of worker bees.

Definitely paint the hive white & provide adequate shade.


Hi Rex,
Thanks for bringing this topic up. It’s one of those questions where you ask the question and you will get 100 different opinions and answers. Me personally, I leave the slide in the top slot all year round. I rather drill in vent holes at either end of the gable roof to allow hot air out. Always ensure that they have a good water supply close and handy.
Not sure if my picture downloaded but I came across it only yesterday. It’s of one of my hives last year on a 48deg C day.

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Thanks for the advice. Great help.

Hi Jeff,

Is this recommendation for humid subtropical or hot-summer Mediterranean climate?

My recommendation is based on my understanding of how bees air condition their hive. In recent years, I’ve reduced my entrances, based on what I read in this forum, which prompted me to take a look at a high performing hive which happened to have a small entrance. It was a hive that was given to me. I didn’t get around to enlarging the entrance. I’m glad I didn’t.

It was @skeggley who once said the ideal entrance size is 15sq.cm, I took it that it was something he read based on studies by someone like Tom Seeley, for example. It’s an easy number to remember, so I’m sticking with that.

In the wild the bees don’t have the luxury of “added ventilation” & they appear to do well without it. However they do choose locations that are well insulated. Therefore my advice would be to not add extra ventilation, but focus more on insulation & ways to keep the outside of the hive cool.

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Thx Jeff. Good info. I have shade and a tree slowly growing beside the hive.

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This depends on climate. In colder parts of Europe, where summers are short and not particularly hot and winters are cold, bees don’t have much of a choice. But here is an example from Mediterranean climate, however 2-3°C cooler than Perth. It is from Bulletin of Insectology 71 (2): 257-271, 2018, Appeal for biodiversity protection of native honey bee subspecies of Apis melliferain Italy (San Michele all’Adige declaration).

Morigerati, Salerno, Italy, September 2013

Isola Vicentina, Vicenza, Italy; September 2013

Looks like they are doing quite well with added ventilation.

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I agree on the amount of ventilation they have. I don’t agree that they’re doing quite well. I’ve seen numerous colonies in similar situations. One thing they all have in common is very little honey stores. They use a lot of honey just keeping the brood warm.

I’d put my money on a colony inside the hollow of a tree surviving a harsh winter before a colony such as in these photos.

You’ve/we’ve all heard/read of people leaving a 100lbs (for example) of honey over a colony just to survive the winter in cold climates. What chance would you give either of those two colonies of surviving a cold winter?

I thought we were talking about coming hot day?

I thought you were defending added ventilation in hot weather. This photo tells a thousand words & explains why I like a colony to use just the entrance in order to keep the inside at the optimum temp.

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Indeed, I do. In Perth on hot days humidity is quite low more often than not. This allows to use evaporative air-conditioning with reasonable success. Bees use the same mechanism to cool their nest. And to be efficient they need to move a lot of air. I do not see how reducing openings may help it.

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Reducing the opening does help, I was like you, I had the same idea, I thought a bigger entrance was better. However the proof was staring me in the face, when observing that high performing hive with a small entrance I talked about earlier.

I think the 15sq.cm opening would be the maximum to aim for.

Do you leave any windows or doors open while your air conditioner is running? Ours is not working, however if it was working & we had it on, we wouldn’t open anything for added ventilation. It’s the same principle.

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Of course I do. I have evaporative air-conditioner and it does not work otherwise.
We are living in very different climates. The lowest mean humidity through the year around your area is about the same as our highest. Your summer is also a bit cooler.

Anyway. Today was 38. Tomorrow’s 41 is coming. The moment of truth :smile:

@Rex, if you are going to close all extra openings, would you mind to take a photo of your hive about this time tomorrow and publish it here to compare results?

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Here’s another point of view…when I first started out with bees, I helped a commercial guy harvest honey…just for the experience. His method was to blow the bees out of the honey supers…it was a cooler day and some of the bees started accumulating on my back…actually quite a few…probably about 1/4 of the bees in your photo. They weren’t attacking and just along for the ride it seemed…from my shoulders down to my waist. I couldn’t figure out why I was warming up so much inside my bee coveralls but those bees weren’t allowing any body heat to escape from my back…what incredible insulators the bodies of bees are! Now, during winter, when I sweep the dead bees from the floor of my beehouse, I throw them on the snow on one spot in my raspberry patch. By spring the accumulated mass of bee bodies is substantial and the snow under those bee bodies is the last to melt. Also, if you are a gardener, dead bees used as a natural fertilizer can’t be beat.

The insulating value of those bees on the front of your hive can’t be underestimated.

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When I see a photo such as TimG has posted above, I instinctively think that hive needs more Flowframe honey supers. There is about 8lbs of bulk bees there which would fill another one or two supers. Plus it appears that this is the 8 frame version of Flowhive. Do you ever add supers if that is the case…assuming there is nectar coming in?

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Hi @Doug1, it is a 10 frame hive in a very strong flow (I was harvesting a full super every 10 days). The day was 48 degrees Celsius! This particular hive didn’t have vents drilled in the top yet. Since adding top vents I’ve never seen anything like that again. You can see I opened the side window to see if there were still bees in there and there were still plenty. so yes I probably should have had another super on top but I have just always worked on harvesting whenever full and only running 1 super.

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Ok, here we go.

Temperature today at my place:
daytempchill

Humidity at 15:00 ~14%.

Hives at 17:00:

It works :wink:

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That’s great news @ABB !

So remind me how are they set up now? No top vent?

Do you bees beard more after dark? I notice no real bearding during the day but after dark there would be a couple of handfuls of bees hanging around outside.