The difference in annual averages calculated from time series or TMY (climData) and iMaps/pvPlanner can be as high as ±2.5%. In special cases higher differences have been observed between data from the older version of the database (iMaps/pvPlanner) and the data computed by the recent model (climData).
We are working on update of the SolarGIS data that is available via iMaps and pvPlanner, so that iMaps and pvPlanner users will have access to most recent and harmonized data. The data for Americas was last updated in August 2014, and data for East Asia and Australia were updated in August 2015. In these regions the difference between climData deliveries and iMaps/pvPlanner data is expected to be within 1%. Update of database for rest of the world is expected to be completed by 2016 (one region at a time).