WMO recommends to calculate the new climate normals as soon as possible. C3S uses the 1991-2020 climate normal as the main reference period for the monthly climate bulletins from January 2021 onward and for the European State of the Climate for 2021. A an example January 2021 was 0.24°C above the 1991-2020 reference period, but 0.43°C above the 1981-2010 period.
Read more on https://climate.copernicus.eu/