Yes, but that kind of temperature is common in my garden too because i live in a closed valley. This year minimum temperature has been -8°C.
I guess the minimal temperatures are only a part of the whole story.
When North-Eastern anticylone stalls here , it is usually for two weeks, with no snow and winds up to 80 km/hour, often day time temperatures are negative. It happens in January -February at 48N, a force of sun is very different from that of Florence at 43N.
My gut feeling is that Shangyuan should be OK at your place.
I think i have read somewhere else, in one of your posts, that your hypothesis for such bad behavior of ichang lemon was the lack of a proper dormancy in warmer climate.
It was written about pure Citrus ichangensis, not Ichang Lemon.
Amazingly its hybrids with 5star citrumelo are much more resistant.
When I had Ichang Lemon ( C.wilsonii from Baches Nursery) in a pot, it gave an abundant harvest of lemons with good smell, but not a lot of juice and many seeds.