National Weather Service United States Department of Commerce

The updated 1991-2020 US Climate Normals have been released by NOAA’s National Centers for Environmental Information (NCEI).  Every ten years, NCEI is tasked to produce an updated set of 30 year averaged climate normals across the country, for climate variables such as temperature and precipitation, as well as snowfall, heating/cooling degree days, frost/freeze dates and growing degree days.

Climate normals are updated every 10 years to characterize today’s climate, rather than track or define long-term trends or changes in climate. Power companies, farmers, builders and community planners are just some of the industries that rely on updated climate normals to develop and sustain their business plans.  NOAA does and will continue to track long-term climate change by using the 20th century average (1901-2000) as the baseline for more recent comparisons. 

Preliminary analysis of the new normals do show changes across the United States, though they are not uniform.

  • Because of long-term climate change, annual average temperature is increasing over time in most places, but changes vary from season-to-season and month-to-month.
  • The new normals are generally warmer across the West, South, and along the East Coast.
  • The new normals are cooler across the Northern Plains and Upper Midwest, particularly during the spring season.
  • Precipitation changes vary considerably depending on the month, season, and location across the U.S., with the strongest change being wetter conditions in the Southeast during spring.

For more information on the updated 1991-2020 climate normals please follow:  Across southern Colorado, the updated 1991-2020 normals mainly follow the warmer and drier trend across western portions of the country. The following tables are a comparison of the updated 1991-2020 normals to the previous set (1981-2010) normals ((1991_2020 normals) - (1981_2010 normals)).

Of note, 1991-2020 snowfall normals (daily, monthly, annual) for Alamosa, Colorado (KALS) were inadvertently omitted in the original version of the updated normals.  NCEI is working on this issue and hopes to have updated snowfall data for Alamosa in the near future.