Citrus trees are not as cold hardy as most fruit trees, but there are a few varieties that can withstand colder temperatures. The cold hardiest citrus trees are the Kumquat, Satsuma mandarin, the Meyer lemon, and the Kaffir lime. These trees can tolerate temperatures as low as -9c (15F). Full article via link below.
https://www.gardenandgreen.co.uk/grow-citrus-fruits
How to grow citrus fruits in a cold climate
Citrus trees are not as cold hardy as most fruit trees, but there are a few varieties that can withstand colder temperatures. The cold hardiest citrus trees are the Kumquat, Satsuma mandarin, the Meyer lemon, and the Kaffir lime. These trees can tolerate temperatures as low as -9c (15F). Full article via link below.
https://www.gardenandgreen.co.uk/grow-citrus-fruits