Looking for Temperature Tolerant Species.

If you check Santa Barbara Orchids site, they have an extensive listing and they tell you which plants are temperate tolerant. There are many plants that are as cold tolerant as Laelia anceps. Most of the Nobile Dendrobiums will take temperatures down to freezing and some below. One grower in Florida reported that his nobile types took temperatures down to 25F with impunity and he bragged about the flowers, although frozen, suffered no damage. Most of the Epi. radicans types will take temps down to 28F. I grow a number of them in the landscape and mine have gone through 31F with no damage.

 

Not sure how I missed this thread...

These didn't seem too bothered by this last winter's minimum of 33F.

Bulbophyllum affine
Bulbophyllum congestum / B. odoratissimum
Bulbophyllum rothschildianum - New growth already emerging
Bulbophyllum wendlandianum - New growth even more developed than rothschildianum

Pleurothallis restrepioides - Just bloomed and plenty of new growth
Restrepia antennifera - New growth already emerging

Here's my most up-to-date outdoor grow list.
The closest outdoor grower to you (that I know of) is in the Monterey Area. Here is his outdoor grow list.
Bill Dobson over in Sydney, Australia has a few Bulbos and several Pleuro alliance orchids on his outdoor grow list.

Miltonia flavescens is a good candidate...

Photo: calimecita

According to the Orchid Culture website...here are some Bulbos that experience average lowest temperatures less than 46F...

Bulbophyllum affine Lindley
Bulbophyllum ambrosia (Hance) Schlechter
Bulbophyllum bracteatum F. M. Bailey
Bulbophyllum collettii King & Pantling
Bulbophyllum elisae (F. Müller) Bentham
Bulbophyllum exiguum F. Müller
Bulbophyllum gamblei (Hooker f.) Hooker f.
Bulbophyllum globuliforme (Nicholls) Nicholls
Bulbophyllum leopardinum (Wallich) Lindley
Bulbophyllum macraei (Lindley) Rchb. f.
Bulbophyllum odoratissimum (Smith) Lindley
Bulbophyllum orientale G. Seidenfaden
Bulbophyllum pectinatum Finet
Bulbophyllum propinquum Kränzlin
Bulbophyllum retusiusculum Rchb. f.
Bulbophyllum rothschildianum (O'Brien) J. J. Smith
Bulbophyllum schillerianum Rchb. f.
Bulbophyllum setaceum T. P. Lin
Bulbophyllum shepherdii (F. Müller) F. Müller
Bulbophyllum sikkimense (King and Pantlin) J. J. Smith
Bulbophyllum thaiorum J. J. Smith 1912
Bulbophyllum umbellatum Lindley
Bulbophyllum weinthalii R. S. Rogers

And some in the Pleuro alliance...

Masdevallia amabilis Rchb. f. and Warscewicz
Masdevallia barlaeana Rchb. f.
Masdevallia chaparensis Hashimota
Masdevallia civilis Rchb. f.
Masdevallia dura Luer
Masdevallia nebulina Luer
Masdevallia nitens Luer
Masdevallia notosibirica Maekawa and Hashimoto
Masdevallia picea Luer
Masdevallia rafaeliana Luer
Masdevallia solomonii Luer and Vásquez
Masdevallia tinekeae Luer
Masdevallia vasquezii Luer
Masdevallia wubbenii Luer
Pleurothallis lilijae Foldats

If you purchase the culture sheets you can utilize this temperature comparison page to visualize temperature compatibility....

37.33N | 100 ft | San Jose, CA --- 26.7N | 3300 ft | Bulbophyllum rothschildianum
View attachment achart_apis_google_com_chart_dd0d27946469b1e0f059a7cf49bec207.
Sources: Orchid Culture, Weather Reports,Temperature Charts

Look forward to hearing how your orchids do outdoors. Hopefully you'll be able to mount a few on trees.