Heat stress is not confined to humans, pets and in particular, dogs are also susceptible where hot conditions are combined with physical activity. And like humans, dogs need to dissipate body heat to prevent hyperthermia and ultimately heat stroke. A common method for dogs to cool is through water immersion in small tubs, human pools, creeks, dams or at the beach, with research supporting this form of cooling. Davis et al. (2019) elevated the body temperature of a sample of dogs (n=9) through brief bouts of treadmill running in 30°C on three occasions, followed by 5mins of 30°C water immersion, laying on a 4°C cooling mat or passive rest. Water immersion produced cooling rates twice that of the cooling mat and three times that of passive rest. Avoiding physical activity during hot weather is a key control to limit canine heat stress. Where this is not possible, providing access to a water body, even if it's relatively warm (30°C), will expedite the reversal of elevated core temperature for your furry friends.
Reference
Davis MS, Marcellin-Little DJ, O'Connor E (2019). Comparison of Postexercise Cooling Methods in Working Dogs. Journal of special operations medicine: a peer-reviewed journal for SOF medical professionals. 19(1):56-60.