Based on the NCAR/NCEP daily reanalysis data of 500 hPa in the Northern Hemisphere since 1960, a dynamic similarity ensemblemean method is adopted to perform extendedrange weather forecast tests in Chongqing. Specifically, the Empirical Orthogonal Functions (EOF) method is used to extract and reconstruct the principle spatial patterns of the geopotential height during the previous few months. Within the domain of interest, candidate years with the greatest similarities are confirmed by comparing the constructed circulation patterns in each year via an analogous precursor method. After altering the temporal length of the early data, the method is conducted again to determine five typical years. In the target area, the daily precipitation frequency is then accumulated in these five years, and further presented by curves. By tracing the peaks and valleys of the curves, the date of regional heavy precipitation can be successfully forecasted in the extended range. Forecast tests indicate that results derived by this method can provide some reference for extendedrange forecasts of precipitation and temperature drop in Chongqing.