In one embodiment, a social networking system maintains a moving average of the number of connection problems, including socket timeouts and failed uploads, per client in a geographic area to determine whether the wireless data network serving the geographic area is overloaded. In response to detecting a network overload, the social networking system may transmit an instruction to the clients in the particular geographic area to enter one of a plurality of traffic throttling modes. In particular embodiments, the social networking system maintains a historical log of network overload conditions, and uses the historical log to generate an estimate of the wireless network capacity serving a geographic area. Thus, the social networking system may preemptively transmit instructions to clients to enter a bandwidth-conservation mode when the estimated traffic demand exceeds the estimated capacity for a particular geographic region.