Pet rabbits who live outside in hutches are particularly at risk at this time of year. Rabbits have fur coats but they only offer so much protection, and in the wild they huddle together in their burrows, sharing body warmth. When they are in a hutch at the end of the garden they don't have this luxury.
Top tips for when the weather gets really cold:
Put a tarpaulin, plastic sheet or an old duvet over the hutch, particularly at night, keep it out of the wind, and preferably bring your rabbit into a shed or indoors while the weather is bad. If your bun has health problems then it really wont stand a chance outside in cold weather.
Line the hutch with plenty of newspapers or old towels, and then fill with lots and lots of hay
Cover the water bottle to stop it freezing. You can buy covers in the pet shop or make your own with bubble wrap, a thermal sock or glove.
Buy a snugglesafe heat pad to use overnight.
When it's cold and dark it's easy to put off feeding and cleaning out the pet rabbit, please take your responsibilities as an owner and do the right thing for the rabbit and make sure it has plenty of food, water and lots of hay. Nothing is warm if it is wet so your cleaning schedule needs to be scrupulous.
Remember, that even in bad weather rabbits will need to exercise every day.