On Tuesday, May 4, NOAA will released the long-anticipated 30-year normals for temperature, precipitation, degree days, and several other variables. These values are updated once every ten years and will cover the period 1991-2020. The previous set of normals was based on 1981-2010. Because of the rising temperature in the US and across the globe, the new normal temperatures are expected to be higher than the previous set, although there are a few places like the north central Great Plains that have actually gotten cooler over time. Here is an article that describes the process of calculating the normals. Tomorrow I will show maps which depict how the normals have changed across the United States.
