Both blended and non-blended series are available. Blended series are series that are near-complete by infilling from nearby stations. They are also updated using synoptical messages. The blended series are the basis for further Climate Services. Details of the blend and update proces are given in the specific FAQ.

Meteorological observations are taken at many stations across West Africa, each day. To minimize the effects of changes over time in the way the measurements were made, a basic quality control is applied before the data is used to analyse extremes. Meta data describing the observation site and instrumentation guides this process.