No one in the valley has responded so I will tell you what I have and why. In December 1990 we had four days with nights down to 12 degrees. My only citrus to survive without damage was my Owari Satsuma Mandarin Orange. It bears heavily every year with fruit with no seeds. I am unable to judge the relative sweetness between other varieties, but we like it, and our great grandchildren who we send bags of fruit when ripe, ask for more. Al

I will second that. We are in the inland East Bay (Walnut Creek) and only got down to 20 degrees during that same epic freeze, but Owari Satsuma didn't have a scratch. Now there is a good chance we won't see temps as cold as 1990s in our lifetime, but there will be cold snaps that are still bad, and this one is tough. The fruit is awesome and prolific.

Thanks for the replies. I may have found the answer on the Citrus forum. I didn't know there was a citrus forum - I'm a newbie. I think I may get a Gold Nugget mandarin. A few people said they're even more cold resistant than the Satsuma! Not that it gets that cold here in the Fresno/Madera area, but every once in awhile we do get a hard freeze. Thanks again for the input!