In summer, there are many things to watch out for:
Heatstroke (you can find a blog on this subject)
Leishmaniasis (you can find a blog on this subject)
Sunburn
Drowning
Intoxication
Envenomation
The temperature outside, in the car and on the ground
For example:
ambient temperature 25°C = floor temperature 52°C
Bear in mind that they don't have shoes to protect their pads.
Good to know:
After every swim:
Rinse with fresh water
Clean ears with dog ear lotion
Dry it
Insist on crease zones
Warning: make sure your dog's eyes aren't red. If so, consult a veterinarian.