You can now add dynamic labels to your Amazon CloudWatch charts that provide richer context on your dashboards, helping you to more quickly identify anomalies in system health and performance. Dynamic labels provide data summaries over the time window represented in the chart and update automatically as the chart is refreshed. For example, adding the average and maximum dynamic labels for a CPU utilization metric across multiple EC2 resources can help you identify anomalies at a glance. The initial set of dynamic labels includes AVG, SUM, MIN, MAX and LAST, with more to follow.
Source:: Amazon AWS