Lilies do need a chill period every winter to bloom, but you cannot keep them in refrigerator like Tulip bulbs. Lilies do not go completely dormant. They will get dehydrated and weak after long storage without the soil.

Thanks for the reply. Does anyone know if lilies are perennials in the SF Bay area? It gets chilly here in the winter (~40s), but it never snows or freezes. Is that cold enough? This is my first year planting lilies, and I wanted to buy more in the fall. However, I don't want to spend a bunch of money if they're not coming back next year.

If you are in zone 7, they will work for you. Frost is not necessary. As far as I remember, Lilies need about 400 hours of low temperature to bloom. People grow them even in zones 8 and 9, but they do not perform as well as in colder climate areas.
BTW, Lilies are perennials in warmer zones, they just do not bloom.

Sorry, I made a mistake. I'm actually in zone 9. I guess I'll have to see how they do next year. If anyone has tips on getting lilies to bloom in this zone, please let me know. Thanks!

I have a friend who gardens in containers on her deck at a small cottage. She lives in a condo in winter. She brings her pots to me to store in my basement. It is cool down there but no where near freezing. Last year, when we took the pots out, the lilies were already 18 inches tall and very pale. I thought they were lost but they greened up for her and bloomed like mad. I checked the pots the other day and once again they are growing. I will be curious to see if they bloom for her this year too. This goes against the information I had.

We can get lilies for reasonable prices here - why not try it and see what happens? Might be worth the experiment. They are so rewarding.

Check out the cornell.edu website. They experiment on bulbs. They did experiments on lilies in different climate zones. Orientals won't grow ell, but some other varieties can be grown in the south.

A high zone is not necessarily an indication of geographic location. I am in a (very northerly) zone 9 climate and lilies of all varieties thrive and bloom perfectly well here. In fact some of the largest commercial lily bulb producers are located nearby!! I even grow all my lilies in containers, which likely exposes them to even higher winter temperatures than if in the ground.

While this is a very old thread and likely the OP as long since vanished, it is important to understand that chill hours only refers to temperatures less than 45F. That is not too hard to accomplish anywhere in the US outside of the most southerly locations

You are correct. Geographic location (USDA) has less to do with it, and is an oversimplification. It has to do with chill hours. I do live southerly and therefore certain plants do not grow here. I find that the Koppen climate system is a very good indicator of what will or will not grow where I live. I am in Koppen Cfa, a subtropical climate with hot humid summers and mild winters. Too mild for certain plants.