The RClimDex software package provides a friendly graphical user interface to compute all core indices defined by the CCL/CLIVAR/JCOMM expert team on Climate Change Detection and Indices (see below).
Tools
RClimdex by the Meteorological Service of Canada.
KNMI Climate Explorer, the Netherlands
The KNMI Climate Explorer presents the possibility to correlate downloadable daily ECA data and extremes indices with a variety of other climate data, like NAO and NINO3 indices, global temperature data, RivDis river runoff data, Hulme/Jones monthly gridded data and selected NCEP/NCAR and ERA reanalysis fields.