In some implementations, a processor may retrieve predicted positioning data and predicted orbital data from global navigation satellite service (GNSS) positioning circuitry of a wireless device in response to a request for device time. The processor may retrieve long-term learning (LTL) data for a temperature sensing crystal (TSX) of the wireless device, the LTL data including S-curve characteristics of the TSX, and the time tracking uncertainty of the TSX. The processor may generate a GNSS-based device time estimate using the predicted positioning data and the predicted orbital data. The processor may perform TSX-based device time processing by updating the GNSS-based device time estimate using a clock signal of the TSX to generate a final device time estimate, the updating based on the retrieved LTL data for the TSX.