It is not possible to list which salvias definitely will get frosted and die. Unfortunately discernment and experience is involved. Some people say they never have frost but sometimes frost can occur unexpectedly.
Latitude doesn’t say everything because height above sea level also enters the equation. I was quite shocked that on one of the Hawaiian islands it is possible to ski some years, there is that much snow. I think that is the same island which has an active volcano and lava flowing down to the sea!! I went there once but it was summer, so no snow.
Age of the plant is an important factor and whether or not the salvia may be waterlogged in a wet winter.
Soggy, cold, young salvias are in line for death in winter or at least lose half of their roots so that when spring does arrive they take a long time to put on much new growth because they have to regrow roots as well.
In Australia there are a few areas that not infrequently go to minus 10C – Canberra comes quickly to mind, Bathurst, Warwick - Queensland, Armidale is pretty cold. Warwick and roundabout can often go to minus 14C. Cities in Queensland away from the tropical coast have very cold nights as they often have desert like weather. (In Australia deserts are not like the Sahara!!!!) I spent a winter near Emerald digging sapphires, days were beautiful but some nights we had ice inside the car with us.
Some salvias from Siberia or similar are fairly likely to survive most cold temperatures but what we don’t always realise in Australia is that plants survive wretched winters because the snow on top of them forms a blanket until it melts and the plant pops out real perky and quickly gets on with flowering. Salvia jurisicii could be an example of that. It will survive dry cold but not wet cold.
It is very hard to get accurate information about what salvias survive or not for marginal areas. I often use comparison with salvias that are moderately tolerant and grown widely, such as involucrata ‘Bethelii’ and whether or not they get frosted. Making a list will be a project to be completed very soon I hope while the evidence is staring at me.
The length of the cold also has a big bearing on whether or not plants succumb to freezing. There are also different kinds of frost which I would have to restudy to explain. You can’t always quote a minus degree and expect the results to be similar each time. However, that is a start for diagnosis.
Cluey gardeners in Canberra for example, occasionally grow amazing plants which I would be extremely reluctant to send there.
These lists are a bit variable depending on how minus you are, but give you an idea and then I can warn you if I think your area might be dodgy, especially for young plants.
Very hardy evergreen plants for frosty areas: africana- lutea, austriaca, blepharophylla, buchananii, canariensis, chamaedryoides, coahuilensis, dolomitica, dominica, disermas, eigii, forskaohlei, involucrata, greggiis & microphyllas, grahamii, grahami purple, leucantha, pratense, Marine Blue, mellifera, nemerosa, polystachya, Purple Majesty, repens, runcinata, scabra, sclarea turkestanica,somalensis,taraxicifolia, thymoides, tingitana,transcaucasica, villosa, viscosa.
Very hardy winter dormant:arizonica, azurea, glutinosa, guaranitica, oresbia, patens, pratenses, przewalskii, superba, transylvanica, uliginosa, verticillata.