How can I keep a fairy garden outside all year long?

I'd be nervous about water and snow damage if you keep the garden outside all year long. If you're really adamant, then how about making a nice little structure-home that you can cover your fairies with to keep them safe from the snow?

There's some winterizing tips here as well

http://minigardener.wordpress.com/2012/10/24/winterizing-your-miniature-or-fairy-gardens/

Depends on where you live. I can, but I am in Southern CA. My girlfriend in Asheville moves hers to her side porches and they have a section in their garage where they winter over a bunch of their plants. For holidays and in the spring, she fluffs them up and refreshes them and they always look beautiful.

North- western Illinois here, I have ground cover and sedum in all my fairy gardens. They come right back up every year. Also, I just pack up all my little figurines and take in only the large glass bowls inside a small outside shed. Otherwise, everything else is left out in the winter. Here are a few picks of mine but can't find other ones right now. Sorry!

Oh! I love the tree! Thank you

Is your fairy garden in the ground? You could move it to a pot or wheelbarrow, then just bring it in the garage in the winter. The decorative items (houses, fairies, etc) will show their wear being left out in winter. For the plants, mulch well and they should come back.

If you have cold, snowy winters, it would be best to bring it indoors or cover it with a tarp to protect it.

Sort of depends where you live. If CA not a problem but if WA you would need to bring it in doors somehow unless you could rig up a cold frame and have some sort of heat inside that to keep the temperature adquate.