NOAA releases new climate normals with warmer & wetter trend for Nebraska
LINCOLN, Neb. (KOLN) - The National Oceanic and Atmospheric Administration recently released a new set of climate “normals” for the United States that covers a 30 year period from 1991 to 2020. These new normals include things like average highs, average lows, average temperature, average precipitation, and average snowfall. It’s this new set of numbers that’s recalculated every decade that is used to judge how daily, monthly, and annual conditions compare to what’s normal for a specific location. Where you likely see these most is in our daily weather almanacs when looking at things like the daily average high or low temperature for the day or when you hear one of your local meteorologists talking about how a day was warmer or cooler than average.
Climate normals are calculated over a 30 year period using temperature and precipitation data from over 15,000 weather stations for daily, monthly, seasonal, and annual averages. The reason why 30 years of data is used is because 30 is considered to be a “magic number” in statistics - a size of at least 30 is recommended for a reliable estimate for a mean or average.
Member nations of the World Meteorological Organization - including the United States - are mandated to calculate these 30 year averages and recommends that they are updated every 10 years to help show subtle changes to the changing climate. They are important not only from a meteorological point of view, but these new normals are used in a wide variety of other areas including things like agriculture, water conservation, energy, as well as travel.
The previous data set that we used for our climate normals covered 1981 to 2010, the new 30 year period is 1991 to 2020, so 20 of the 30 years included in the newest data set are the same as the previous one. The changes we see - including in Lincoln - across the United States are generally fairly subtle with gradual increases or decreases in things like temperature, precipitation, or snowfall. Specifically for Lincoln, our new normals show us as just a bit warmer and a bit wetter than the previous set of normals.
The images below show the changes to Lincoln’s average highs, average lows, and average temperatures by month as well as a look at the annual and seasonal changes. It isn’t much, but you can see that each month has slightly warmer average highs and lows, and our annual and seasonal average temperatures also had slight increases.
From a daily perspective, temperatures did not change all that much with most days seeing an increase of a degree or two for their respective average highs and lows. One change that was noted was that Lincoln’s average high has increased to 90° from July 11th to July 27th - the previous data set kept Lincoln’s average high at 89° throughout the entire month of July.
Slightly wetter weather was also noted in the new climate normals released last week. Again, it isn’t much, but Lincoln’s average precipitation increased from 28.95″ for the year to 29.34″. Our average snowfall increased from 25.9″ to 26.0″. You can see the monthly and seasonal changes in the images below.
From a national perspective, most of the country saw a slight increase in annual temperatures. The northern Plains - including the Dakotas and into parts of eastern Montana were really some of the only places that saw a slight decrease in average temperature over the 30 year period. Changes in precipitation were much less uniform, with much of the western U.S. and the desert southwest seeing drier conditions with slightly wetter conditions for the northern plains and for the eastern third of the country.
This new set of climate normals helps give a better baseline for the climate right now, which will continue to change over the next 10 years just like it has over the past 100 years. A new set of climate normals will be released in another 10 years in 2031.
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