Description: Root Mean Square Error (RMSE) is a measure of the difference between model forecasts and observations. The closer that a point is to an RMSE value of 0.0, the more accurate the contiguous U.S. (e.g. CONUS) 2-m temperature forecast that was valid on that particular date. Valid dates are shown along the x-axis. Different colored lines represent different forecast lengths, according to the key. The shorter the forecast length (Day 1 = 24 hours, Day 3 = 72 hours, etc.), the better you would expect the forecast to be. Day 1 forecasts, for example, are usually the closest to 0.0 (i.e., perfect).

Description: Mean Error (i.e., Bias) is a measure of the average difference between model forecasts and observations. If the bias line is above 0.0, it means that contiguous U.S. 2-m temperature forecasts valid on that day were too hot. If the bias line is below 0.0, it means that contiguous U.S. 2-m temperature forecasts valid on that date were too cold. If the bias line is equal to 0.0, if means that contiguous U.S. 2-m tempeature forecasts were neither too hot nor too cold. Valid dates are shown along the x-axis. Different colored lines represent different forecast lengths, according to the key.