Systems, methods, apparatus, and articles of manufacture to improve timestamp transition resolution of watermarks are disclosed. An example system includes a watermark detector to detect watermarks and a decoder to decode timestamps in respective ones of the watermarks. The example system also includes a timestamp transition resolution enhancer that estimates a first transition window indicative of a transition between a first time period to a second time period based on a first one of the timestamps and a second one of the timestamps. The timestamp transition resolution enhancer also estimates, when the first transition window does not satisfy a threshold, a second transition window indicative of a transition between the second time period and a third time period based on the second timestamp and a third one of the timestamps. In addition, the timestamp transition resolution enhancer determines a first mapped transition window based on an intersection of the first transition window and the second transition window, and sets the first mapped transition window as a reference time transition window for subsequent time periods.