There are a few things you can with your standard langstroth roofs to help keep the bees comfortable during a heat wave. There are also a few design modifications well worth considering when building your own roofs that may further protect your bees from the intense mid-summer sun.

Can't the bees just fan the hive to keep things cool?

Yes, they will certainly try, but as amazing as they are, even bees have their limits. If it gets too hot they will shut down brood production, and in extreme situations it is possible to lose colonies.

To get a sense of how hard your bees are working to keep cool, it's relatively easy to place a thermometer at your entrance(s) to gauge the temperature of the air being pushed out of the hive.

IMGP1869

Keep in mind brood rearing requires a temperature in the 33-36°C (91 - 97°F) range. If your entrance temperatures are significantly above that, you may wish to take the temperature near the brood nest to see if they are winning the climate control battle.

Even when things are not too extreme, why not take a few simple steps that might save your bees from wasting time and energy?

Creating ventilation

Adding an upper entrance and tilting a telescoping cover back is certainly a simple way to offer some heat relief to a colony.

langstroth upper entrance with lid tilted back

Painting metal roofs white

With the ambient temperature at 33.8°C (92.8°F), a plain metal covered roof was a very hot 46.1°C (115°F), while a metal rooftop with a coat of white latex paint was 38.3°C (101°F):

temperature of painted metal hive roof

Providing shade

In my region, it is generally advised to locate your bees in full sun. For those living further south, the conventional wisdom is to try and provide mid-day shade. If, like me, you have chosen a full sun location, you can provide shade only when the temperatures are unusually hot.

A simple, if temporary, way to add shade is to lay a few tree branches on top of your hive. I chose branches from a tree species known to be invasive in my area.

Using branches to provide the bees a bit of shade

Within a short period of time, this dropped the temperature of my painted roof down 3.4°C to 34.9°C (95°F).

Of course, the leaves will soon dry out and shrivel. If you are experiencing an extended heatwave, you may wish to consider a more durable solution.

Build a double-level roof.

The idea here is that the top-level creates a solar shield that effectively shades the bottom level, while simultaneously creating an air gap through which a breeze can pass, thus minimizing thermal conduction of heat downwards into the hive.

With the ambient temperature at 33.7°C (92.7°F)

Ambient temperature near the beehive

The metal covered, upper-level of the roof was 46.7°C (116°F), while the temperature below was a cool 31.4°C (88.5°F)

Temperture under a 'warre' style beehive roof with solar shield

The inspiration for this style of roof comes from the warré hive.

Build your roofs with corflute under the metal

Corflute is the kind of material election signs are usually printed on. The air pockets in the material help insulate and minimize thermal conductivity.

Using an old printing press sheet and coflute to protect the beehive from rain and heat

Use a Quilt or other form of insulation

A warré style quilt helps keep heat in during the winter, but it also helps keep heat from the sun out of the hive during the summer.

Thermometer

The thermometer I used throughout this post is a regular digital thermometer that one might use in a kitchen.

The main quality you are looking for in this tool is ability to adjust to ambient temperature relatively quickly. You can find one here on Amazon.

July 11

We started checking the new box we seeded with a frame last visit.

IMGP1793Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

They had four combs well on their way and a fifth one started. All of them perfectly straight.

IMGP1794Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

IMGP1796Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

IMGP1797Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

IMGP1799Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

fresh white waxPhoto by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

A little less than I thought they might have built in two weeks but still pretty good. The only problem is I wanted them to start using this box for brood. Instead it was nectar and a bit of pollen. I guess the seed comb didn't have enough eggs to entice nurse bees and the queen to come down.

Fortunately, there was still good amounts of brood up top. A frame full of eggs and young larva:

IMGP1802Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

Two others full of capped brood:

IMGP1807Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

IMGP1811Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

Capping honey on the fourth frame:

IMGP1814Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

To me this looks like the queen is not able to lay as much as she might like and they are putting more energy into building up stores than building comb than I would like. I checkered the combs in the bottom box to see if that would help put an emphasis on comb building. It would also help ensure they build those combs straight on the frames.

We opened up the entrance reducer a bit.

July 12th

I felt I needed to add another seed comb to the nuc and see if my luck at baiting the queen to come down will be better the second time. I was worried about the potential of a crisis developing from a small population and reduced space to lay if they didn't start making new brood comb right away.

I had to uncap a little bit of honey to make space for my bait frame in the nuc box. A little was enough and I was able to do it quick and smoothly without much fuss.

Rain water had accumulated in the container I had left with crushed comb. Bees were drinking from it, but it was also attracting wasps and hornets.

July 16th

We had entered a heat wave. It was 33 degrees Celsius.

The sweet white clover blooming very close to the hive was very popular with the girls.

Sweet white clover in leasidePhoto by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

Despite the heat, there didn't seem to be significant amount of bearding. Of course their numbers are not very high. Just steady fanning at the entrance.

IMGP1860Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

The temperature on top of the roof was high:

temperature of painted metal hive roofPhoto by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

But the temperature just above the brood was perfect:

Beehive temprature above the brood nestPhoto by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

Warmer air, however, was recorded at the entrance:

IMGP1869Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

They had a decent sized comb going on the bait frame. Some nectar on top, but a good number of eggs under that.

IMGP1871Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

I had modified the bar I use to hold my warré fram in the lang nuc with wooden blocks to prevent extra comb being built on the sides of the frame. It worked perfectly. In the bottom box They now had seven combs in the works. I seeded the new warré comb with the eggs in a new box in between the nuc and the other warré box.

I opened up the entrance a little bit more and placed some tree branches on the roof to provide some relief, if only temporary from the heat.

IMGP1877Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

This did quickly drop the temperature on the outside of the roof.

IMGP1876Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

Either the bees and wasps drank all the water in the feed container or it evaporated. The heat also melted the wax in there:

IMGP1862Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

I scraped it clean, added in a float to prevent drowning and left a bit of water:

IMGP1880Photo by: Shawn Caza / CC: Attribution-NonCommercial-ShareAlike License

The bucket water feeder system I had left them when we first set up the bees still had some amount of water. I'm yet to see a bee use it. My design probably needs some improvments.