The AN daily and monthly time series datasets for all elements will commence using the new Norm91 (1991-2020) normals as predictor grids (replacing the 1981-2010 normals) starting on January 1, 2021. However, these changes will not be made (retroactively) until mid-January, 2022. The new time series datasets will be termed AN91m and AN91d. The LT81m monthly time series datasets will not be updated for the time being, and will continue to use the 1981-2010 normals as predictor grids. See our updated datasets document for details on these datasets.