The National Oceanic and Atmospheric Administration (NOAA) has updated the US Climate Normals to better reflect the changing climate and its influence on day-to-day weather.
The US Climate Normals – a large suite of data products that provide information about typical climate conditions for thousands of locations across the US – now use the 1991-2020 baseline period as the standard reference to compare variations in temperature, precipitation, etc, to the 30-year average.
The move is in line with a World Meteorological Organization recommendation that the 30-year standard reference periods should be updated every decade.
Until the end of 2020, the most current and widely used standard reference period for calculating climate normals was the 30-year period 1981-2010. WMO’s recent Services Commission meeting recommended that the new 30-year baseline, 1991-2020, should be adopted globally and pledged support to members to help them update their figures. Many countries in Europe have already switched to the new baseline.
However, for the purposes of historical comparison and climate change monitoring, WMO still recommends the continuation of the 1961-1990 period for the computation and tracking global climate anomalies relative to a fixed and common reference period.
For the purpose of Paris Agreement on climate change and its temperature targets, WMO also uses the pre-industrial era as the baseline for tracking global temperature increase in its annual State of the Global Climate report. Thus, the average global temperature in 2020 was about 1.2 °C above the pre-industrial (1850-1900) level.
To read more about the US Climate Normals update, click here.
