What are 30 year climate normals? Why do we need them? How do we use them? Our new time frame for our 30 year climate average is from 1991-2020.
The Chippewa Valley Region Airport is the benchmark climate station we use here in Eau Claire. The newest data shows that we averaged higher precipitation totals and more snowfall over the past 30 years.
The previous annual snowfall totals from 1981-2010 was 48.0''. We now average 55.4'' of snow each year. Precipitation totals have increased from 30.98'' annually to 32.99''; a 2.01'' increase.
Overall, average annual temperatures changed by -0.1º. The new 30 year average is now 44.7º compared to 44.8º from 1981-2010.
In short, calculating climate normals gives us all a benchmark for comparisons during any given weather day. Typically, we use them to compare how today's weather is doing compared to what we've normally seen over that set 30 year average.
According to NOAA, "Thirty years of U.S. weather station observations are compiled, checked for quality, compared to surrounding stations, filled in for missing periods, and used to calculate not only averages, but many other measures." You can learn more from their explanation of climate normals, here.