AWS provides latency numbers between regions, AZ's and within an AZ in network manager. Useful to have as a latency baseline and to see if they have any issue.
https://docs.aws.amazon.com/network-manager/latest/infrastru...
https://docs.aws.amazon.com/network-manager/latest/infrastru...
AWS also provides dashboards that shows what regions/services are down, and history tells us those are not to be trusted for precisely the same reasons.