Historical Climate Trends
The Historical Climate Trends product provides a comparative seasonal or annual analysis for a specified climate division or state. Long term averages are taken from NCDC's monthly and annual temperature and rainfall datasets. These long term averages are depicted in each chart as a horizontal line in the middle of the chart. 5-year moving averages of seasonal (or annual) values are plotted in comparison to the long-term average as red or blue curves for temperature and green or brown curves for precipitation. When looking at the temperature graphs, a red curve indicates a warmer period than the historical average, while a blue curve is a period that is cooler than the historical average. On the precipitation graphs, a green curve indicates a period that is wetter than the historical average, while a brown curve is drier than the historical average.