Looking for reports for daily, weekly and monthly availability - just need these for monthly reporting. It would only be for certain regions, not all nodes.
Use Orion Report Writer and then use the filter tab (filter on the Region, its located under Custom Property). Save a copy of the report and it will be available in the Web Console.
You can then use Report Scheduler to email the reports!
We use a report which rolls up the outage time monthly. It looks like this:
Let me know if this tech ref helps you get what you need. Also there are a lot of availability reports on Content Exchange.