Honey bees on a camping trip

Once upon a time two colonies of honey bees decided to spend an autumn weekend away from the suburbs. They packed their tents, sleeping bags, and plenty to eat before they took off into the foothills. One colony went into a sheltered valley. The other colony flew up to a wooded ridge.

Before the first colony pitched its tent, rain soaked everything. Their sleeping bag, tent, food supplies, and even their wings were drenched. But with daytime highs in the 60s and nighttime lows in the 40s they weren’t too worried; after all, they wouldn’t freeze. But the rain had chilled them, so they closed up the tent as tightly as possible so no more cold air could get in. They huddled together inside their wet shelter—cranky, miserable, and too cold to eat.

Their friends higher up didn’t get wet at all. Everything inside the tent was dry. Still they worried about the weather—with daytime highs in the 40s and nighttime lows in the 20s—they knew they had to be prudent. So they opened the ventilation flap to prevent their breath from condensing inside the tent and snuggled warmly together beneath the star-studded sky telling wasp stories and drinking honey wine.

By morning, many of the bees in the wet colony had died of hypothermia. Those remaining were too cold to move, even to get a bite of breakfast. Those that could move at all could barely put one foot in front of the other. Their blood sugar dropped from lack of food and they stopped thinking or even caring. They became disoriented. More would die before the weekend was over.

Up the hill, frost rimed the twigs and the sun glinted off the ice crystals. Inside, the colony laughed, stretched their wings, and shared breakfast. They had enjoyed a spectacular night and were now rested and eager. . . .

Keep ’em dry

Okay, I’m guilty. Once again I have personified the bees. But there is a lesson here. Would you, a human being, be better off in a wet 40-degree sleeping bag or a dry 20-degree one? It’s really no contest—and bees are the same. Dry bees can survive very cold temperatures, whereas wet bees collapse quickly. If you have a soggy hive with water dripping from the roof onto the cluster, there is a good chance they won’t make it through the winter.

Evaporation is a cooling process, so as water evaporates we feel cold. If you get out of a pool or out of the shower, you feel the chill almost immediately. But conduction also plays a big role. Water is much denser than air, so water draws the heat from your body much faster. If you wrap yourself in a wet blanket that is at room temperature, you will feel colder than you would without the blanket at all.

When humans experience a drop in core temperature they lose the ability to control their muscles and ultimately lose their ability to reason. Honey bees are similar. And even if your bees survive the cold temperatures, a wet hive is a culture plate for fungus and molds, and a breeding ground for a number of pathogens, especially the brood diseases.

It is true that the amount of humidity in a hive is influenced by a number of factors, including the hive type, size, climate, and local weather patterns. But if you open your hive and find water inside the roof, under the inner cover, or collecting on the top bars, your hive is suffering from moisture overload and needs ventilation. No one is healthy living in a dank, humid, dark, moldy, airless box—not even honey bees. Plugging every hole to keep out the cold could be the worst thing you ever do for your bees.


Related Posts:

What history tells us about hive ventilation
Ventilation Part 1: A hive is not a tree
How to make a moisture quilt for a Langstroth hive
The best ventilated gabled roof
To wrap or not to wrap


  • I see so many people going back and forth on the topic of screen bottom boards and if you should leave them open in the winter. What is your stance? I live in NW Georgia about 60 miles north of Atlanta so we can typically have a 40-50 degree difference between the coldest part of night to the warmest part of the day. I’m not positive but I believe we also have high humidity also.

    • Claudia,

      Basically, I leave them open. In the past, I have closed them up when the temperature dropped into the 20s for more than a day or two. Once it warmed up into the 30s again I opened them up. I don’t really know if that precaution is necessary—probably not. Usually our nighttime temperatures are in the 30s and I don’t consider that a problem. I am much more worried about high humidity in the hive.

      The large fluctuations in temperature that you mention cause lots of condensation because the warmer air during the day can hold a lot of moisture, but the colder air at night cannot, so it ends up condensing.

  • Rusty,

    The speaker at our November meeting, the KY state apiarist, said the same thing that you emphasize. His words were that dry bees in a cluster when it’s 20 outside are fine, but wet bees at 30 degrees will die. He also pointed out that a mountain camp feeder with dry sugar helps by absorbing condensation. I assume this is true with candy cake also.

    Beekeeping really builds on a lifetime of other work, because we scramble to put the horses & goats up when it rains with the temperature dropping. But if it’s cold and sunny, they fuss to be back outside. Unfortunately, climate change is bringing us more warm, wet winters than ever before.

    Moisture quilts just make so much sense. Thanks!


  • Ventilation is the nearest related category I could find for my topic. My beekeeper friend came to rob the hive on our land one very fine sunny, cloudless, blustery spring day about 1 pm, probably the hottest time of the day in the dry tropics city of Townsville, Australia. Our spring is like summer of many countries. I have looked at the weather bureau statistics and the wind was blowing at 37 km/hr and gusting up to 56km/hr, temperature 28 degrees Celsius. The wind direction was such that it was blowing directly from the east into the opening of the hive unblocked by any trees or bushes. Not only was our friend suited up, he was still stung many times including through the gloves which surprised him. Even though there has been no rain in our dry season for the last 5 months, he was still able to gain about 11 kgs of honey and still leave some as food for them. The honey is a golden yellow which I am told is due to the yellow pollen of the Eucalypt trees in flower at present. The hive is in the centre of land between 3 dams within about 30 – 90m from the hive and lack of water does not seem to be an issue. I give this extra background information to show that the hive seems to be productive and has been in that spot now for nearly 2 years. Initially we had a hive of large quiet bees, then after a year the bees became small and a bit buzzier, but now they seem to have increased in size but are still not as quiet as the initial bees. Does a strong wind into a hive with a super on top normally upset the bees and make them angry? After all I have read about how fussy bees can be, I am reluctant to move the hive to a more sheltered position as it does seem to work even if the temperature and wind are not optimal.

    • Merilyn.

      If the hive location has been working well, I wouldn’t move it. Why fix what isn’t broken? In my opinion, it is probably not the wind that caused a change in the bees’ size and behavior, but probably a different queen. If the queen was superseded, a new queen with slightly different genetics could cause the difference. I’m just guessing, of course, but the wind patterns probably haven’t changed much over the course of two years, but the queen may have.

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