Please note that the graph of anomalies are only represented the annual values ​​in years when there was no failure monthly, ie 12 years with monthly mean values​​, those years in which data are not presented in the graph of anomalies, this means there was at least one month of incomplete data and therefore does not present the relevant technical anomaly, which does not mean that there is no data in the remaining months of this year.

The rules of the WMO (WCDP No. 10 / WMO TD No. 341, 1989), indicate that there should be a calculated clearance monthly if more than three failures consecutive nights or more than 5 alternate, this month, which means that whenever there is, at least 4 consecutive days, or 6 alternating with no data in one month can not calculate the monthly or the annual tabulation. The monthly averages are displayed in the upper graph of the results thus at least 18 years of data in each month, for available stations.

For further information we suggest to consult the guide practices climatological WMO (WMO No. 100, 3rd Edition, 2011). "