Surf information is imperative for safety, coastal planning, and engineering applications. Daily surf observations made primarily by lifeguards along the north shore of Oahu, Hawaii, have been digitized for the 35-year period from 1968 to 2002. The subjective nature of observations introduces uncertainty. This study analyzes the temporal consistency and estimates the accuracy of the observations. Comparisons are made to breaker heights derived from significant wave height and dominant wave period as measured by the nearest environmental buoys, one of which has a series length of 22 years. The comparison pairs are picked from the high-surf season of October through March for days dominated by long-period swell. The analysis shows the surf observations are consistent in time. The uncertainty is between 10% and 15% of the reported height, and the magnitude of the error increases with surf height. Given the large range in breaker heights on the north shore of Oahu, this error is small. Although the visual observations have low precision and only represent daylight hours, the time series are longer and more continuous than other breaker height data for this region. Thus, these observations represent the best available resource for understanding regional surf climatology, which is described in this study.