Time zone data is obtained from clients, such as web browsers, which interact with a server, and used to classify metrics of the clients such as response times. This classification technique does not require that a mapping of IP addresses to geographic location is available. Metrics from the clients are communicated from the server to a manager, which aggregates the metrics for each time zone. The manager can automatically associate geographic descriptors, such as names of cities, with the metrics in a report such as in a user interface display. If a partial mapping of IP address to location is available, the report can aggregate metrics which are grouped by IP address separately from metrics which are not grouped by IP address. The user interface display can be automatically populated with selectable nodes which allow a user to selectively view the metrics.