Keeping Hives Cool in the Heat

The hot summer months are just around the corner. Before they get here, however, this is what you need to know to keep your bees happily producing honey and not thinking about finding a cooler place to call home.

Bees Work Hard to Regulate Temps

When the temperatures begin to soar, bees work hard to maintain optimal temperatures and humidity within the hive, especially within the brood area. That’s one of the reasons you see so many bees concentrated in the brood area - they’re working to keep the temperatures in the 91° - 97°F range. If it gets too hot, however, they’ll begin to shut down brood production which can lead to hive failure.

During extreme heat conditions, you may lose your colonies for a couple of different reasons -- the bees may not make it, or they may abscond, looking for a better (i.e., cooler) place to set up a new colony.

How Bees Eliminate Heat in the Hive

How do bees combat heat inside the hive?

When interior temperatures in the hive become higher than optimal, you may notice bees hanging from the hive in clusters that resemble beards. This may mean the bees are preparing to swarm. It can also indicate, however, that it’s a little crowded in the hive and the bees are congregating outside, providing more space for ventilation inside the hive and enjoying the cooler temps outside.

When it’s hot, worker bees deposit water droplets on the edges of the comb and in a thin film on top of the sealed brood comb. They then fan it to create air currents to set up an evaporative cooling system to cool the nest and to prevent melting of the wax comb. Additionally, they may exhibit behavior that’s referred to as heat-shielding by pressing their bodies against the brood nest wall to absorb localized heat.

Despite their best efforts, however, bees can only do so much to eliminate heat inside the hive. So, why not give them a hand?

Make Sure Bees Have Adequate Access to Water

Bees use water for several purposes in the hive, using as much as a few liters each day. As already stated, they need it for evaporative cooling purposes. They also use it in the creation of brood food. When water is needed, a forager bee begins to carry water to the hive and will do so for the remainder of the day as long as a water-carrying bee is available to give her load of water to.

 A close and convenient water source makes this easier for the bees and gets them back to foraging for nectar and pollen more quickly. Check out our blog post, Creative Water Solutions for Your Beekeeping Yard, to see just how easy it is to provide adequate water access.

Provide Shade

The easiest way to provide shade is to have placed the hive under the canopy of a shade tree. If the hive is not positioned under a shade tree, however, you can set up a shade tent or place a large umbrella over the hive when hot weather is forecasted, especially when predicted for long periods. Don’t move the hive to a shadier location ... the bees can become disoriented.

You can also build a structure, such as a pergola or a grape arbor, over the top of the hive to provide shade.

Ensure Adequate Ventilation

Although venting a hive in hot weather may emit the scent of honey and increase the colony’s vulnerability to robbing activities, it may be necessary to prevent overheating and melted combs. An easy way to vent a hive is to install an upper entrance.

If the bees don’t use this entrance, it can be covered over with a piece of screen to prevent robbing activities and still allow the heat to escape.

A screened bottom board can also be used to increase ventilation, allowing air to freely flow through the bottom of the hive.

Metal Roofs Increase Heat

If you’re using a metal roof on your hive, it will conduct heat and increase temperatures in the hive. At the very least, you should convert it to a wooden cover and paint it white. White reflects heat, whereas, black absorbs and holds onto it. The Bee Smart Ultimate Hive Cover, however, is the perfect solution:

• Lightweight — lighter than wood
• Will not rot
• No assembly required — ready-to-use
• Provides passive ventilation

Best of all, its double-wall construction and internal airspace provide insulation, keeping the hive warmer in the winter and cooler in the summer.

Provide Insulation

Just as it does in our homes, insulation will keep a hive warmer in winter and cooler in the summer. Place insulation, like an old quilt or bubble wrap under the hive’s roof to help stabilize temps in the hive’s interior. The Bee Smart Ultimate Hive Cover has this insulation built-in. You can also add an insulation box to the hive. (Here is a video showing you how to insulate an existing hive box.)

Consider Hive Placement

Besides shade, other considerations should be taken when determining the best hive placement to prevent overheating.

Avoid placing the hive where airflow will be impeded, such as next to a building.

Avoid hot areas on top of or near a radiating heat mass, such as pavers, concrete slabs, brick walls, greenhouse, etc.

Extreme Measures

When temperatures soar and you become concerned, you may need to take extreme measures to keep your hives cool enough. These measures may include:

• Using a fan to cool the hive
• Placing a bucket of ice on top of the hive box — do not put it inside the hive
• Draping wet towels over the hive box lid — will need to be rewetted occasionally. Wet towels and a fan used together provide additional cooling abilities.

These extreme measures are rarely required, but in an emergency, it’s good to have a few tricks up your sleeve. If a heatwave settles in and you’re concerned for your beehive, don’t be afraid to use one of these methods to reduce heat in your hive.

The Bees Have It

Most of the time, your bees will be able to take care of maintaining the temps inside the hives themselves. When temperatures move into triple digits, especially for prolonged periods of time, however, your bees may require a little assistance.

General Questions About Hives Cool in the Heat

How do bees prioritize their tasks during extreme heat conditions?

Bees prioritize their tasks during extreme heat by adjusting their roles based on the hive's needs. Some bees focus on water foraging to aid in evaporative cooling, while others ventilate the hive by fanning their wings to create air currents. This dynamic role adjustment helps the hive efficiently respond to heat stress.

What are the signs that a hive is beginning to fail due to heat stress before it's too late?

Early signs of hive failure due to heat stress include a noticeable reduction in hive activity, especially foraging, and an unusually large number of bees clustering outside the hive, known as "bearding." Regular monitoring of hive temperature and bee behavior is crucial to detect these early warning signs and take timely action.

Can the color of the hive exterior influence its internal temperature, and if so, how?

Yes, the color of the hive exterior influences its internal temperature. Dark colors absorb more heat, while light colors, especially white, reflect sunlight, keeping the hive cooler. Painting the hive in lighter shades helps maintain a more stable and cooler internal environment, particularly in hot regions.

How does the choice of materials for hive construction affect its thermal regulation capabilities?

The choice of hive construction materials significantly impacts thermal regulation. Natural materials like wood provide better insulation compared to synthetic materials, helping keep the hive cooler in summer and warmer in winter. Thicker and denser types of wood offer even better insulation properties.

Are there any natural or organic materials that can be used for insulation instead of synthetic ones like bubble wrap?

Yes, natural or organic materials such as straw, hay, or wool blankets can be used for insulation. These materials are excellent insulators and can be placed under the hive's roof or around its sides. They not only stabilize the hive's internal temperature but also promote environmentally friendly beekeeping practices.