Q. What is the latency between Azure regions?
A. There is no official document that outlines latency between regions however you can perform a test to get a rough idea by using some Azure latency/speed test sites from within an Azure VM in a region.
For example create an IaaS VM in a region, such as South Central US. Then within that VM browse to:
- http://www.azurespeed.com/ - Basic latency
- http://azurespeedtest.azurewebsites.net/ - Blob storage latency
Since you are running the site from within a region the numbers found are the latency from that region to the other regions. Below is an example of one latency site running from VM in South Central.