|Snapshot of the Beta version of the DAYCLI monitoring tool|
In mid-2018, WMO Members were invited to participate in the trial phase for the monthly reporting of daily climate data (DAYCLI) via the WMO Global Telecommunication System (GTS). Some 20 Members volunteered, and the trial started in January 2019.
The U.S. National Oceanic and Atmospheric Administration (NOAA)/ National Centers for Environmental Information (NCEI) provided participants with access to the DAYCLI software demonstration package. DAYCLI messages are consistent with national climate records, thus allow greater comparability between regional and global climate data analyses and products and national ones.
Over the course of the trial, the main challenge concerned differing definitions of “climatological days”: The trial phase confirmed that different national climate observing and data management practices had been established historically in the absence of global coordination. The trial, therefore, revealed the need to attach information on the hour and period of observation to each of the climate variables reported.
Subject to endorsement by WMO constituent bodies, an extension of the trial phase is planned while preparations for the start of the pre-operational phase - tentatively scheduled for the second half of 2021- will start soon. A global DAYCLI monitoring tool is envisaged – to be implemented in close collaboration with WMO Information System (WIS) Global Information System Centres (GISCs). A new BUFR template is also intended to allow for the submission of appropriate observational metadata.
 The Binary Universal Form for the Representation of meteorological data (BUFR) is a binary data format maintain by WMO.