I think you can use the "Average" mode of a gauge indicator.
Each gauge indicator contains the RefreshMode and RefreshRate properties. When the refresh mode is "Average" then the indicator shows average value for values which were assigned to the Value property of indicator during the time which assigned to the refresh rate.
I have attached a sample solution which uses the marker and needle indicators. The marker uses values as is, but the needle indicator uses the "Average" feature.
Also I would recommend to take a look at the "Indicator Refresh Rate" example of our demo application.
It is placed in the "Visualization -> Gauge -> Features" section. You can start the demo application locally or you can use the following link to start online examples:
the Telerik team