Thiessen Method Another method of determining precipitation within a given area is the Thiessen Method. This method is more accurate than the previous one because it accounts for any non- uniform distribution of monitoring stations and weights each station's contribution differently. For instance, this method assumes the value of precipitation of an area within a watershed is most accurately reflected by the measurement of the nearest station. Furthermore, it provides a simple way of delineating the area that each monitoring station represents. (Refer to attached handout for a description of the Thiessen method) 2. Using the Thiessen method, determine the average annual precipitation (m ) of Lake Okeechobee. Make use of the map of Lake Okeechobee in Figure 2.1. Use the grids to estimate the area