I have brought in my Adeniums too right after our first cold rain in November. I let it get that rain, since it has been quite a very long time since we had rain, then allowed it to dry out after it stopped raining and temps returned to the low 60's then, afterwards indoors they went by our south facing window. It is often the overnight temps that concerns me, as we started to go colder overnight after that and at one point getting a sudden frost warning. Glad it was indoors already by then. My usual threshold to bring them in is if I see our overnight temps starting to go below 50F. When it is colder there is increased humidity, and too cold and wet is not good for Adeniums, it can easily rot them.
Right now my plants still holds on to it leaves, and is getting good sunlight by our south facing window so it is growing some new leaves, while dropping older ones, so it is not yet ready to sleep. But usually come late Dec to Feb it stops doing anything, still holding on to some remaining leaves, but it is dormant at that point. I wait for any sign of new leaf growth before I attempt to resume normal watering and I prefer to do that once I have it outdoors again to enjoy the sunshine, usually this would be in late April to early May. It has enough stock up water in its caudex, at least for my plants, so am not too worried it will dry up.
However, my plants are a bit older. As I understand it the younger ones, may require a bit more water than usual, since it has not formed a good caudex yet.
