Today is the hottest day of the year so far and could beat the hottest day on record - so police are advising residents on what to do if they see a dog in a hot car today.
The county is set to reach highs of 36C and police have warned that dogs can be killed very quickly in this weather if they are left in a car.
Both Nottinghamshire and Derbyshire Police have said they if you see a dog in a hot car today you should call 999 immediately.
Sergeant Gavin Berry, of Nottinghamshire Police, said: "It can take less than ten minutes for the temperature inside a car to more than double, this could prove fatal to the dog even if a window is slightly open."
Police have also told dog owners not to risk their dog's lives and not to put them in hot cars and to keep them out of direct sunlight for long period of time.
Sergeant Berry said: "As people continue to enjoy the summer holidays, we just want to remind dog owners of the dangers of leaving their animals inside hot cars - even for a few minutes.
"Temperatures inside vehicles can rise rapidly, which can make dogs very distressed.
"Avoid walking your dog on hot pavements, as their paw pads can easily burn, and you should keep your dog out of direct sunlight for prolonged periods of time."