beekeeping equipment

An instant-read hive thermometer for winter colonies


Do you want to know if your colony is alive without using an infrared camera or a stethoscope? Try an instant-read hive thermometer. This neat idea was sent to me by Ken Armes, a beekeeper in Ontario, Canada.

Ken wanted to know if his colony was surviving, but he didn’t think he could get an infrared reading through the insulating material wrapped around his hive. The harsh temperatures of an Ontario winter require good insulation, but the thick layers block both heat and sound, making it hard to assess what is going on inside. But with a little experimentation, Ken discovered an inexpensive way to learn if his bees were alive. He wrote:

Use an electronic cooking temperature device with a probe, insert the probe into the top entrance and check that the temperature is higher than the outside ambient temperature. You’re not looking for a large difference, just an indication that something is generating heat inside. I was getting a temperature difference of two to four degrees Fahrenheit, so I kind thought the hive was okay. Now the girls have confirmed it.

The confirmation came in the form of a warm spell that brought his bees outside in droves.

An idea worth a try

There’s nothing I like better than a creative idea, so this morning I took my little instant-read thermometer outside to give Ken’s idea a try. I don’t have a digital thermometer, but I thought the so-called instant-read thermometer might do the trick.

I always wonder where they got the name “instant-read” because in the digital age, this old-fashion type takes forever to register. Yes, “forever” doesn’t mean what it used to, so I’m talking about 30 seconds or so. But when you’ve got the oven door open, checking on a freshly-baked delicacy, forever seems like the right word.

First I put the thermometer on the back of the pickup and the temperature registered 37 degrees F. Then I took the thermometer to the hive behind my pump house which I knew was alive, although I’ve been concerned about it’s strength.

Spinning the dial

Just as Ken suggested, I stuck the business end of the thermometer into the upper entrance and waited. The first thing that happened surprised me: the thermometer started to spin. It was dancing around and rolling over. I had placed it so I could read it upright, but in no time it was upside down. I fixed it, then it rolled again. My bees were playing with it.

In a few more seconds the bees were coming out of the entrance and climbing all over the thermometer. I took a couple of photos but the bees blocked the dial. I had to keep taking photos until I got a clear view: 92 degrees! In less than a minute, the reading had increased over 50 degrees.

And a free sting, too

When I was done, I pulled the thermometer out, and instantly got stung on the hand: an instant-sting thermometer.  “Sorry guys.” I said, “Spin-the-dial time is over.”

I thought Ken’s idea was clearly worth a mention because it is inexpensive, works with insulation, gives you a lot of information, and is fun to watch. The thermometer I have is similar to one they carry at Amazon, just a dial on the end of a rigid probe, about five inches long. I’ve had it for years without ever realizing it would be useful for beekeeping.

Thank you, Ken, for a brilliant idea.

Honey Bee Suite

An instant read hive thermometer showing about 37 degrees F.

According to my instant-read hive thermometer, the outdoor temperature this morning was about 37 degrees F.

Hive thermometer showing about 92 degrees F.

After about a minute in the hive, the instant-read thermometer read over 90 degrees F. Behind the dial is plenty of space for the bees to come and go.



  • Hi Rusty,

    Thank You very much for your highly informative articles on beekeeping. I really enjoy reading and learning as much as I can about beekeeping. I am entering my third year. First year went so well I thought …this is great I got 50 pounds of honey had a new hobby I loved. Second year lost two hives to feeding them in July which created a terrible robbing frenzy. This winter has been crazy where I live south of Albany, New York. For the past week and a half the bees have been out foraging and bringing back loads of pollen in their pollen baskets. I made fondant and added it just as insurance and they ate the first batch all up in the active week. When I opened up to check on the there must have been a few hundred bees clinging to the inner cover again with all of this activity still going on. My question is the hive has one deep and one super on now….should I add another medium to give them more room or should I just let them be? I have read and heard that when all of this pollen is being brought in they are usually raising brood. But I do not want to stress them out or create problems if they don’t need help. I am just concerned with all this warm weather. They must be finding a good pollen source near the forests by my home. Any advice would be greatly appreciated.


    Tony L.

    • Anthony,

      If it were me, I would leave them alone for now. You’re bound to get more cold weather in New York, at least through March. Then around the first of April I’d open up on a warm day and see what they need for space.

  • The probe! I see it a possible harpoon.. be very careful sticking the probe into dark spaces where the cluster could be located and unseen… remember this where the queen is located.

    Also, I monitor hive temperatures and humidities each winter. Often dead out hives with honey stores still within, will be warmer than the ambient temperature long after the sunsets. These hives will also warm faster than empty test hives.

    • For heaven’s sake, Bill. I bet someone couldn’t skewer a bee with thermometer in the dark if his life depended on it.

      • Rusty,

        Sure, skewer maybe not be the problem, but blind poking a probe into unknown spaces is just asking for trouble. That’s my two cents.

    • Bill, have you actually verified that dead out hives warm faster than empty ones? I would think that the more cold mass that has to warm up, the longer it would take to warm up.

      • More mass means greater heat capacity. A hive with lots of honey in it will take longer to heat up, and once it’s warm, it will take longer to cool down. You will get more rapid temperature fluctuation from an empty hive.

        • Because the honey, unless in a prolonged cold spell, never cools down to match the ambient temperature, it warms fairly quickly again. On those days, after a prolonged cold spell, sure the empty hive will warm much faster and the end of the day dump the heat much quicker. I’m just adding this to the conversation so you know that heat by itself is not always proof of life.

          • Bill,

            I agree that heat by itself is not always proof of life, but what you describe here goes against the laws of physics. The only way honey could stay above ambient temperature is if it were generating heat by some biological process like bacterial degradation. Perhaps your honey is fermenting? Honey has a high thermal mass which is why a lot of honey in a hive can stabilize daily temperature fluctuations. But unless some biological process is going on in the honey, like decomposition, it cannot create heat. Since it cannot create heat, it eventually has to reach ambient temperature and it cannot possible heat up faster than a dead air space in the same environment. It’s an impossibility. Read up on thermal mass, heat capacity, specific heat capacity, insulators and the like. Any basic physics text will work.

  • That is awesome. I will remove the stethoscope from my Amazon order and use one of my instant-read thermometers. Love your website!!!! Helen

    • Jim,

      Not common, but it happens. They came out to see what the commotion was about. Remember, it was 90+ in there. So after a quick check, they all went back in.

  • “Instant read” is an oxymoron. I have found that instant read digital thermometers take as long to register the temperature as the mechanical thermometer you used to measure you hive temperature. Just a marketing tool – if you build it, you gotta get them to buy it!

      • But Rusty, that’s the point! One does not need an “instant read” thermometer – the non-digital, non-instant mechanical one you have in your kitchen works just fine.

        • You guys just don’t get it. The mechanical, non-digital thermometer with the dial that you see in the photo are marketed and sold under the generic name “instant read” thermometers. Go look on the internet. There are dozens of types, and that’s what they are called. The word “digital” is not in the name, just “instant.” Where have you guys been? Don’t you cook?

          • I am an excellent cook. I also am an empiricist, and check out advertising claims. In my experience digital and mechanical thermometers are about equally non “instant” – they take several seconds to register a temperature.

  • Rusty,
    Love your thoughtful and ingenious posts!
    One question about the insta read thermometer–my upper entrance is just below the inner cover below the moisture quilt with a honey super below that (for winter food). Will inserting it into the upper entrance still work?
    Thanks so much!

    • Maggie,

      Hot air rises, so the warmest part of the hive outside of the cluster is right above the cluster. That warm air will leave the hive through the top entrance and vent holes. So yes, it will work. One thing though, I wouldn’t put an inner cover below the moisture quilt; you’re blocking it from doing its job.

  • The thermometer that you show is a “dial” thermometer, NOT a digital thermometer. It works by mechanical means of physics, not by “digital magic” and there is nothing instant about it. However, monitoring a bee box with a thermometer is a no brainer good idea.

    • M Tobin,

      Right. Ken used an electronic thermometer and I used a so-called instant-read thermometer which, like I said, isn’t instant at all. But his electronic one gave me the idea for using the little one with a probe. I mention the dial a number of times in the post, so I don’t really know what you’re worked up about.

      Also, M Tobin, I didn’t name it. “Instant read” is what they are called. It wasn’t my idea.

      Lots of negativity in the air these days. Take it home.

  • My point exactly. But that isn’t what Bill claims. He says a full hive warms up faster, overlooking the fact that it starts from a higher temperature than does an empty hive, because it also cools more slowly.

  • I wish they had a hive “tender timer” but, what a great idea! I will have to add this to my repertoire. Those winter stings are cherished (by me, anyway) I look forward to trying it out, and sharing the idea with others.

    Thank you, Ken! And THANK YOU, Rusty!

    • Thanks Natalee. It’s funny, I’ve been doing the complicated things and not the simple things. And the simple things are often the best.

  • We’ve had some crazy warm weather here in New England this past February. So on those 45-70 degrees sunny days, I get a pretty good idea about which hives are are still with us and which are not. Those bringing back pollen are a clearly indicate strength, but one with no pollen harvest but a decent amount of activity? That might be a dead out and robbing. Oh well.

    I will definitely check the “F-Hive”, see if those girls are viable or if it is just a food source and will need a re-stocking.

    Until now (pre-thermometer) I often surmised a thriving hive by how many dead are on the snow outside: Corpses on the outside indicate life on the inside. Reminds me of Monty Python, “Bring out your dead!”

  • I LOVE this idea! I have a stethoscope and a flir but never get tired of collecting data in the winter. I’m going to try it with my infrared thermometer.

    • I tried my infrared thermometer but I couldn’t get a clear “shot” because the hive entrances are protected by the telescoping covers.

  • Rusty,
    Yikes, on Friday of this week, the high is supposed to be 47 (eastern WA).
    Should I take the inner cover off, then?

  • Has anyone tried an infrared surface thermometer? It seems that the exterior surface of the hive would be warmer near the upper entrance of near the cluster relative to other parts of the hive. You can buy an infrared surface thermometer from Amazon for $10-$12.

    • I did, and it didn’t. Gave it to my brother, who is a contractor and can use it for finding heat leaks.

  • Hi Rusty,

    Being a first year beek nearing the end of winter, I see fairly decent indicators that my hive is doing well. Cleansing flights on mild days, lots of activity in and out—even on a sunny, but windy day like today in the low 40’s there’s activity.

    I added fondant on two occasions on mild days in December and late January hoping to boost their food stores because I made a near fatal mistake of not feeding them during (dearth) August. I know, believe me, I have beaten myself up about this ever since. I’m hoping and praying they have enough food to make it through the rest of winter. A valuable lesson learned. I keep a journal for inspections, as well as for outside temps and flight activity—and take a lot of photographs.

    My girls have been very active all week during this mild, sunny weather here in Litchfield County, Connecticut and I’ve watched them bring back sac after sac of yellow and whitish colored pollen. I have a mouse guard in place, a cedar pillow on the top in a screen box (with holes) for moisture and airflow but no inner cover, therefore no upper entrance. I know your position on upper entrances, and wonder when I should put mine out. With the understanding that temps will be in single digits here this weekend, and I’m sure we’ve not seen the last of snow quite yet, do I wait until I’m ready to open it in April to be safe? The hive is not wrapped, but guarded by an electric fence due to the black bear population that we try to co-exist with here.

    Besides the inner cover timing, when do I add the entrance reducer? Should I plan to add protein patties to help fortify them at the April inspection and treat for varroa? Is there anything else I should plan on doing that I haven’t mentioned?

    Yep, first year beers are just such rookies wanting to do the best for our bees.

    Many thanks and appreciation for your honey bee suite insight. I always look forward to reading them!

    Warm Regards,

    • Donna,

      Since you have accounted for air flow by having upper ventilation, there is no need for an upper entrance. For years I went without them, but I started using them again a couple years ago. It turns out my colonies do well with them, but they are by no means mandatory. You can add one if you like at any time, but I prefer using an Imirie shim rather than an inner cover. An inner cover between the brood boxes and the moisture pillow partly defeats the action of the pillow if warm air condenses on the underside of the inner cover rather than being collected by the pillow.

      I don’t quite understand your question on the entrance reducer. I put mine in the late summer or fall (based on robbing by bees or yellowjackets), leave them in all winter, and take them out in early spring. So I wouldn’t add one now unless there was some issue with robbing.

      If a lot of pollen is coming in, you probably don’t need protein patties. Pollen is superior for bee health, so I would go with that. However, if you have extended periods of cold weather after spring brood rearing has commenced, then you may want to add a patty to tide them through.

      I believe Varroa treatment should be based on test results, so plan on doing a sugar roll (or ether roll) during a warm spell.

  • Incredible!! It’s 44 degrees in the shade today, 3-2-17, Cincinnati, Ohio, and I took readings on 4/4 hives. the one I have been concerned about measured 60 degrees, others 90 + and my super hive (which is sure to swarm this year) measured 98 degrees!! Thank you so much for this fun tool. Who knew how easy it was to measure viability of a hive!

    • Julie,

      You are doing fine. I’m still having issues with my comments counter. I’ve tried about 25 suggestions and, so far, nothing works.

  • Just stumbled on this post, very cool [or warm I guess]. So here’s a question about our TBH [oh sigh]. It is a smallish hive 12 bars total combs now after being gifted to us in May 2019 as a swarm from an existing over-wintered hive also in a TBH. Entry hole(s) are at one end with all but one plugged right now. [December] Currently broodless we assume. The bees are pretty much clustered into 9 of the 12 bars dead center as expected. Used an 8″ temperature probe and inserted into entry hole with ambient temperature of 45 degrees today. Temperature on what would be below the combs was 55 degrees. Inserted the same probe through propylis ever so gently about 4″ in and got a temperature of a little over 80 degrees. And the question is you may wonder, would this be considered a reasonable temperature all things considered and might you think additional insulation placed under the sliding bottom board might be a good idea if I can actually lift the entire hive without doing more harm than good. The hive has an inner cover lid with insulation under it, AND an additional layer of insulation between the cover lid and the roof. This will be our second winter with bees and we are both a bit paranoid given we lost our very first hive just after the first of the year.

    • Gary,

      A broodless cluster maintains a core temperature of around 85°F (29°C). With brood, they keep the core about 93°F (34° C). Sounds like you’re in the ball park.

  • If a hive is a dead out, its external and internal temperature will rise and fall as the air temperature rises and falls, with a lag. In the late afternoon, when the air temperatures start dropping, the inside of the hive might APPEAR to be warmer than the outside, because the inside of the hive hasn’t had a chance to cool down, especially if there is honey inside.

    It is best to check the temperature of the hive multiple times during the day. If there is a functioning cluster, it will usually be warmer than the outside. Also, remember that the cluster moves around, so you can drill a small hole on the opposite side of the hive from the upper entrance and check the temp. there too. In addition, the temperature reading can be exaggerated if a few bees are on the probe. If the bees are in a tight cluster, you will get a true reading of the air space temp.

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