Dragon Fruit

culebra says...
Hylocereus are highly frost intolerant.
might survive.
they grow extremely vigorously when it warms up.
In some warmer areas (like inner Melbourne suburbs) they can grow outside with no protection fine.
likely you should either put it in a very sheltered spot or else provide some form of frost protection for it. or both.
better still would be growing it under cover like under an eave of the house or similar.
they are epiphytes and generally do not grow in the ground, better potted, but i have seen it done successfully.
do not see your climate as a restricting factor, I have seen them grown (and fruit) in Tasmania.