The SPCA had to break two dogs out of hot cars yesterday - with one distressed pup having been stuck in the vehicle for 40 minutes.
"Yesterday was the first nice day we have had in Wellington in a number of days and along with that we also had a concerning number of cases of dogs in hot cars in just one day," said SPCA spokeswoman Jessie Gilchrist.
"Our inspectorate team received over six calls from concerned members of the public about dogs in hot cars, and had to break two dogs out of vehicles for their safety.
"If one good day is like this, we don't want to imagine what the rest of summer is like."
One dog was found by inspectors trying to crawl under a seat to the nearest bit of shade it could find.
"It was drooling, and had urinated in distress," Gilchrist said.
The dog was taken back to the centre for a full vet examination.
"Yesterday it was around 21 degrees, in 10 minutes the dogs in those cars would have been sitting in 31 degree heat, in 30 minutes it would be 40 degrees. One of those dogs was in the car for over 40 minutes."
On top of this, the owners of the dogs were abusive to inspectors, she said.
"It was a shame to see the owners of the dogs becoming abusive to our inspectors, questioning what they were doing, telling them their pets were fine, and asking who was going to pay the costs of the broken window.
"We are looking out for the welfare of their pets and seeing easily preventable cases like these, met with abuse is disappointing."
Gilchrist urged people not to leave their pets in hot cars.
"It takes only minutes for a pet left in a vehicle on a warm day to succumb to heatstroke and suffocation.
"Most people don't realise how hot it can get in a parked car on a balmy day, let alone a sweltering hot summer day."
On a 30C day, temperatures in a car with windows down can reach 39C within five minutes, and 49C in half an hour.
"If the purpose of your trip is not for your dog, then please leave them at home."