A method and system for detecting an indoor threshold transition in a positioning state. The method may be executable using one or more processors and comprises, upon detecting a pattern of magnetic anomaly characteristics associated with a sequence of position changes of the mobile device, extracting the pattern, comparing the extracted pattern with a stored magnetic signature associated with the indoor threshold, and based on the comparing, inferring that the mobile device is one of transitioning in position and has transitioned in position across the indoor threshold.