Every ten years, the United States and many other countries release a new set of 30-year average temperature and precipitation values, which are called “climate normals”. They are intended to capture the average conditions for the last 30 years and are used by many industries, including agriculture, to make decisions about what kind of weather and climate to expect. Using a 30-year period is done to make sure that the average reflect recent conditions and not the climate of 100 years ago. This May a new set of normals for the US will be released, as they replace the 1981-2010 period with the 1991-2020 records. Since temperatures have been rising in the US since the 1960s, that means that the new normals will be warmer than the old ones. This article from NOAA explains the process and shows some examples of how the new averages will compare to the old ones.
