Having said that, there are still a few things you (as a new owner), should know about cold weather rabbit care if your rabbit(s) are outside.
Rabbits tolerate the wintertime much easier then they tolerate the summer. My bunnies are always active in the winter, happy to see me and playing in their cages. In the summer, they move slowly and sprawl out, panting, to keep cool. Baby bunnies can freeze to death, so we're going to be bringing pregnant Gracie in when it's time for her to have her babies this weekend. But adult rabbits do very well in the cold if you know how to care for them.
THEY NEED WATER
Rabbits cannot survive without water, in the summer and in the winter. As the temperature drops below 32*F the water bottles will need to be defrosted. You'll need to check on the water bottles more often during winter, maybe even defrosting them several times a day. Luckily, in Everett, WA, I only need to defrost my bottles in the morning after the cold night.
In water bottles, the nozzle always freezes first. Even if it looks like the water hasn't frozen yet, the nozzle might be.
Crocks or heavy bowls are easier to defrost then water bottles. All you need to do is smack them against something to get out the chunk of ice, and refill it. The water bottles will need to run under hot water for a few minutes. I switch out my glass water bottles with plastic ones in the winter, so the ice expanding doesn't cause the water bottle to crack. The crock, however, will need to be filled up several times per day, as the water will freeze quicker in a bowl then in the bottle. Rabbits will gnaw or lick the ice in the bowls so they will still be getting water if you don't defrost it immediately.
THEY NEED TO BE HANDLED
Even in the cold, icy wintertime the bunnies need to be played with, pet, cuddled and held just as much as usual. This is a good reason to bring them inside; if you think you won't be able to handle them properly with them living out in the cold.
Handling your bunnies every day, even more, lets you know how they are doing. If they have any injuries or if they are sick, you need to take care of that immediately. Rabbits can go downhill VERY quickly.
Handling also keeps your rabbit from becoming antisocial, bored and getting bad habits, such as chewing on the cage bars (which can lead to malocclusion).
WHAT AND HOW MUCH SHOULD THEY EAT IN THE WINTER?
Rabbits eat more in winter then in summer, to maintain their body heat. Provide them with more then you normally feed if they stay in good weight, depending on how cold it gets where you live. Feed your rabbit more if they seem to always be famished or underweight.
In the winter, it is good to always provide hay for your rabbits. Hay can offer some protection against wind, extra warmth for young bunnies and something to nestle in if it's just really, really cold.
REASONS TO BRING YOUR RABBIT INSIDE
~You begin to neglect your rabbit (don't handle as often, don't feed enough, don't defrost the water when it needs to be defrosted)
~You are a breeder and want to continue breeding through the winter. Baby bunnies can freeze in under 30* weather
~The water bottles keep freezing and the rabbits hardly get any water before it freezes again
~Your rabbit gets sick or behaves in a sickly manner
Your rabbit will be fine in the cold, no matter HOW cold it gets, as long as you continue to care for it as normal and it stays healthy.