Abstract
The network of about 5600 cooperative stations in the United States provides the baseline temperature data upon which most climatologies are based. Since the data serve between 40 000 and 50 000 primary users each year, and untold secondary users, data review, a part of data quality control, is an important consideration. This paper reveals the magnitudes of data changes made during different levels of data review efforts. With a full-scale effort, only about one-half of one percent of all values are altered in some way. However, the magnitude of daily changes can be large, thereby affecting the computation of monthly statistics and affecting users' needs for daily data.
