How latency routing in Route 53 works?

There's a good explainer here https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy-latency.html

For example, suppose you have Elastic Load Balancing load balancers in the US West (Oregon) Region and in the Asia Pacific (Singapore) Region. You create a latency record for each load balancer. Here's what happens when a user in London enters the name of your domain in a browser:

1. DNS routes the query to a Route 53 name server.
2. Route 53 refers to its data on latency between London and the Singapore Region and between London and the Oregon Region.
3. If latency is lower between the London and Oregon Regions, Route 53 responds to the query with the IP address for the Oregon load balancer. If latency is lower between London and the Singapore Region, Route 53 responds with the IP address for the Singapore load balancer.

Latency between hosts on the internet can change over time as a result of changes in network connectivity and routing. Latency-based routing is based on latency measurements taken over a period of time, and the measurements reflect these changes. A request that is routed to the Oregon Region this week might be routed to the Singapore Region next week.