The Dangers of Strong Sunlight:

While a nice, sunny day seems perfect for a gentle stroll, strong sunlight brings its own serious hazards to dogs and humans, such as sunburn, dehydration, and heatstroke. 

(Photo from Fido's Day OutLinks to an external site.; photo captured 2018-04-04)

On a sunny day, strong insolation can cause sunburns that increase in severity the longer the exposure. Not only are sunburns painful, they increase the risk of skin cancer in both humans and dogs. Yes, dogs can also get sunburned! Sunburn on a dog manifests as pink/red skin that is often tender and painful to the touch, and is most likely to occur on the areas that are not fur-covered, such as the ears and nose.

Also, strong sunlight often brings with it warm temperatures, especially during the hot spring and summer months. If ill-prepared, going for a long walk in these conditions could lead to heatstroke, which is characterized by a body temperature that is higher than normal (>41 degrees Celsius for dogs, >40 degrees Celsius for humans). Dogs, being covered by fur, are especially prone to heatstroke, so they should be monitored at all times during a walk for symptoms of such; these include excessive panting, muscle weakness, and vomiting. If untreated, heatstroke can lead to organ failure, cardiac arrest, and death in both humans and dogs. 

How to Minimize the Hazards from Strong Sun/Warm Temperatures:

To avoid sunburn, humans should apply high SPF sunscreen to exposed skin, and reapply it throughout the walk as needed. The same should be done for dogs (applied on areas that are not fur-covered), except with pet-safe sunscreen. 

(Photo credit: Barkpost.comLinks to an external site., image captured 03/16/2018)

To minimize the risk of heatstroke, always have a water supply on hand to prevent dehydration. It is also important to avoid overexertion, which can include excessive exercise, or walks that are too long in duration. If temperatures are extremely warm (to the point where being outdoors would be unsafe), the best solution may be to simply keep walks and exercises indoors altogether. If the walk must take place outdoors, then it should not be scheuduled during the hottest time of the day (which would likely be in the afternoon, when the sun is at its highest point). Cloud cover should also be taken advantage of; a cloud-filled sky will block out more direct sunlight than a clear sky, thus reducing the amount of insolation received. 

(Image by Aleksandra Dabrowa from ShuttershockLinks to an external site.; Image captured 2018-03-16) 

When is Strong Sunlight Most Likely to Occur?

Strong sunlight is most likely to occur when a high pressure system is in the area. This is because high pressure systems are associated with clear skies, meaning there are less clouds that would obstruct solar insolation. This doesn't mean that dog walks should be avoided when there is high pressure (especially since the weather associated with it is generally far better than that associated with low pressure systems), but rather that extra caution should be exercised in order to ensure safe walking conditions for both dog and human.

Another instance in which hazardous strong sunlight can occur is when there is a lot of snow on the ground. This is because snow can reflect more than 90% of light, making insolation a much greater hazard than when the ground is bare. As such, the danger of snow on the ground in regards to insolation should not be underestimated.