Temperatures below -4C could become life-threatening for small dogs if they are left outside for a prolonged period of time, according to researchers in America.
Academics from Tufts University, in Massachusetts, produced a 'weather safety scale' highlighting the temperatures dogs can safely withstand.
The cut-offs for safe temperatures vary depending on the size and breed of the dog, with larger, Northern breeds able to handle colder temperatures than smaller dogs with thinner coats.
The advice comes as Burton remains in the grip of some of the UK's coldest temperatures since 2012, while some parts of Scotland have plummeted to -14C in January.
According to researchers, any temperatures between -1C and 4C can be 'potentially unsafe' for small and medium dogs, depending on their breed.
For larger dogs, the potentially unsafe cut-off is between -6C and 1C.
Advice for these conditions is for dog owners to keep an eye out for their dog's wellbeing while out and about.
The next cut-off, 'Potentially dangerous weather', is -4C for small dogs, -4C to -9C for medium dogs and -9C for large dogs.
In these conditions, dog-owners are advised to take extra care to keep your dog warm and take all necessary precautions.
Temperatures become 'potentially life-threatening' at anywhere bellow -4C for small dogs and anywhere below -9C for medium and large dogs.
In these conditions, dogs can be let outside briefly to use the toilet but should not be exposed for any prolonged period of time.
And the researchers also warned that these temperatures change by up to 6C if there is wet weather.
This means, for example, that a small dog could only withstand 2C if it is raining before conditions become potentially life-threatening.
The researchers published the figures as guidelines for dog owners, but added: "Common sense must be used to take into account the duration of exposure to any given temperature when assessing risk."