RSPCA WA has seen a 55 per cent increase in calls flagging concerns for animals without proper shelter.
As a result the animal welfare charity are urging pet owners to rug up or bring your furry friends inside over winter.
"During the winter months, hundreds of abandoned, neglected and injured animals will rely on RSPCA WA for shelter, warmth and care," Executive Manager Animal and Enforcement Operations Hannah Dreaver said.
"Right now, we are at around 85 per cent capacity for dogs and 70 per cent for cats. We need this space for urgent cases of cruelty brought in by inspectors over winter.
"So we're really urging pet owners to do the right thing and protect their animals from the harsh weather.
"We don't want to hear about any more animals struggling with sickness or pain due to the cold."
Ms Dreaver suggested pets be brought indoors where possible during winter - even just to a sheltered room like a laundry or closed-in garage.
"If your pet sleeps outside, make sure they have access to weatherproof shelter, with lots of cosy blankets, that's away from draughts and raised off the ground to protect from flooding," she said.
"Pocket pets like guinea pigs and rabbits will benefit from some extra bedding to snuggle into, and even farm animals with thick winter coats should have access to shelter to protect them from the rain and wind."
Ms Dreaver said that some dogs might benefit from wearing a coat at night when it is very cold, depending on if they are used to having this on.
"Just make sure any pet clothing fits properly, and be mindful that some dogs don't like wearing clothes," she said.
"For horses, a rug could help keep them warm and dry, if you are going to use them though, please ensure to check them regularly to ensure they stay dry, are fitted properly and no straps have come loose.
"Cold weather can be really rough on senior dogs and cats with arthritis. If your pet is showing signs of stiffness, chewing or licking certain joins, or having difficulty going up or down stairs, talk to your vet."
If you see a pet in poor condition this winter, or without shelter from the rain and cold, please report this to RSPCA WA online or by calling 1300 CRUELTY (278 3589).