I believe theymos is the only one who handles these types of issues and if he isn’t around to deal with any problems causing downtime, he won’t be around to update any status website. Theymos also has created threads in meta advising of any downtime.
If the forum were to use one of these downtime notification websites, I would suggest statuspage.io, but the forum is really not complex enough to warrant using one IMO.
It can also have some functions updated programmatically that would turn red if for example the DNS was unaccesible, or clouldflare was slow etc...