As temperatures soar across the UK, many dog owners know to watch out for hot pavements, dehydration and overheating to keep dogs cool. But you may have noticed another weather term cropping up more and more: wet bulb temperature.
While air temperature tells us how hot it feels outside, wet bulb temperature gives a more accurate measure of how effectively humans and animals can cool themselves down. And when it rises too high, it can become dangerous – especially for dogs.
Here’s what every dog owner needs to know:
Jump to:
- What is wet bulb temperature?
- Why is wet bulb temperature dangerous for dogs?
- What wet bulb temperature is dangerous?
- How can you check wet bulb temperature?
- How to protect your dog during hot, humid weather
- Signs your dog may be overheating or experiencing heatstroke
- What should you do if your dog is overheating?
What is wet bulb temperature?
Wet bulb temperature combines air temperature and humidity to measure how effectively moisture can evaporate.
When we’re hot, our bodies cool down through sweating. Dogs don’t sweat in the same way as us. Instead, they mainly rely on panting to regulate their body temperature.
When humidity is high, evaporation becomes much less effective. This means both humans and dogs struggle to lose heat, even if the actual air temperature doesn’t seem extreme.
So essentially, wet bulb temperature reflects how difficult it is for the body to cool itself naturally.
Why is wet bulb temperature dangerous for dogs?
Dogs are particularly vulnerable because they have fewer ways to cool down than humans.
Panting works by allowing moisture to evaporate from a dog’s tongue. But when humidity levels rise, that evaporation process becomes less efficient, making it harder for dogs to regulate their body temperature.
This means a dog can become dangerously overheated even on days that don’t feel exceptionally hot.
The risk increases for:
- Flat-faced breeds, such as Pugs, Bulldogs and French Bulldogs
- Older dogs
- Puppies
- Overweight dogs
- Dogs with heart or respiratory conditions
- Thick-coated breeds
What wet bulb temperature is dangerous?
Scientists often cite a wet bulb temperature of 35°C as the theoretical upper limit of human survival during prolonged exposure.
For dogs, however, problems can occur at much lower levels.
How can you check wet bulb temperature?
Many weather apps and specialist weather websites now include wet bulb temperature, heat index or humidity readings.
Even if a forecast doesn’t specifically mention wet bulb temperature, it’s worth paying attention when high temperatures coincide with humidity levels above 60–70%, as these conditions can become a real challenge for dogs.
While wet bulb temperature may sound like a technical weather term, it highlights something dog owners should take seriously: heat isn’t just about temperature.
Humidity can make it much harder for dogs to cool themselves down, increasing the risk of heat exhaustion and heatstroke. During warm weather, keeping an eye on both temperature and humidity could help protect your pet from potentially life-threatening overheating.
And as Dr Linda Simon, resident vet at Pooch & Mutt, points out:“No dog will suffer from missing one walk, but heatstroke can become life-threatening very quickly.”
How to protect your dog during hot, humid weather
Dr Linda urges owners to follow a simple three-step rule during hot weather:
- Check the temperature
- Check the pavement using this seven-second test
- Check your dog
"If the air’s too warm, the pavement fails the hand test, or your dog’s already panting before you leave, skip the walk."
Walk early or late
Choose cooler parts of the day, such as early morning or late evening, when temperatures are lower.
Dr Linda says: “As a rule, I would urge owners to avoid walking during the hottest part of the day altogether and to be especially careful once temperatures reach the mid-twenties. No dog will suffer from missing one walk, but heatstroke can become life-threatening very quickly.”
Don’t assume evenings are safe
Wet bulb temperature can remain high long after the hottest part of the day has passed, particularly when humidity levels stay elevated and surfaces continue to radiate heat.
Dr Simon explains: "The mistake many owners make is assuming that if the sun has gone in, it must be safe. But pavements, roads and built-up areas can hold heat for hours, meaning an evening walk can still be risky."
Provide plenty of water
Ensure fresh drinking water is always available both indoors and outdoors.
Create cool resting spaces
Use shaded areas, cooling mats and well-ventilated rooms to help your dog stay comfortable. Try these products to keep you dog cool.
Avoid strenuous exercise
Even energetic dogs may struggle in humid conditions. Swap long walks for shorter outings and indoor enrichment activities.
Never leave your dog in a car
Cars can become dangerously hot within minutes, even when outside temperatures seem moderate.
Signs your dog may be overheating or experiencing heatstroke
Dr Linda urges owners to act quickly if their dog shows signs of overheating, including:
- Heavy or excessive panting
- Drooling more than usual
- Lethargy, weakness or wobbliness
- Bright red or very pale gums
- Vomiting or diarrhoea
- Confusion or collapse
Heatstroke is a veterinary emergency and can become life-threatening if left untreated.
What should you do if your dog is overheating?
If you think your dog may be suffering from heat-related illness, move them somewhere cool as quickly as possible and seek veterinary advice.
Dr Linda advises: “If you think your dog is overheating, move them into shade or a cool room. Offer small amounts of water and pour cool, not ice-cold, water over the whole body (but not the head). You should contact a vet straight away, as heatstroke is an emergency.”
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Cara is Commissioning Editor at Country Living, covering everything from style and interiors to sustainability, artisans and the great outdoors. She has previously worked for Good Housekeeping, Homes & Gardens, House Beautiful, Prima and Red, and has an MA in Magazine Journalism from City University and a BA in Music from the University of Oxford. Follow Cara on Instagram @caralaskaris or Linkedin.
