I have grown some noid dudleyas before, and I find in my area, they cannot really stand our rain and cold, and I think that is how I lost them. But if kept just cool and dry, as with most succulents they will fare better, just not in the low 20's range. And even the extreme heat they did not like. Best conditions is in the 50F to 80F range, with some shade in my area during our hottest summers. Humidity is not an issue here during summer, way too dry here.
With the semps, they suffer in our heat here, but there are some varieties a bit more tolerant. They can certainly endure our winter rain and cold here, as long as I really prop them in a rocky medium so it drains very fast.
