Exploratory Data Analysis of Accuracy of US Weather Forecastes

How reliable are the weather forecasts? Based on data collected from onehundred and thirteen cities in the United States over 38 months on threevariables, maximum temperature, minimum temperature and precipitation,accuracy of the weather forecasts was examined. The same day forecast hasbeen extremely accurate, especially for the maximum temperature, whilethe forecast errors and variability increase as forecasts go further out indays. Some cities have larger or smaller forecast errors than the others.For long-term weather forecasts, the maximum and minimum temperatureforecast errors has decreasing correlations overtime, respectively; However,the correlation between maximum and minimum temperature forecast errorsis positive and increasing overtime. The 7-days forecast errors of precipitationare pretty accurate.