Are atmospheric “greenhouse” effects apparent in the climatic record of the contiguous U.S. (1895‐1987)?

The temperature and precipitation climate records for the United States have been examined. These records consist of area‐averages across the contiguous United States and northern plains. They are based on as many as 6,000 stations. Time series of these data were tested for constancy of the mean using the Spearman rank test and two‐phase regression. Test results indicate that overall trends are near zero. The only evidence for a long‐term trend is in Fall precipitation for the contiguous United States. This trend appears to result from higher fall precipitation during the period 1970‐1987 compared to the remainder of the period (1895‐1969).