Documentation Product guides Time series and TMY data

Data format

Time reference

By default, we use UTC (Coordinated Universal Time) as a time reference for Solargis time series datasets. UTC is equivalent to GMT (Greenwich Mean Time), therefore UTC+1 equals to GMT+1. 

In the case of hourly time series data and TMY data files, we also deliver the data with time reference set as longitudinal time zone, calculated using longitudinal reference of the site as follows: longitude°/15 (rounded value). Please note that in many regions the time zone based on the longitudinal reference will deviate from the legal time (for example in Chile, the time zone used is UTC-3:00, however longitudinally it belongs to UTC-5:00). The only reason for having data in longitudinal time zone is to facilitate easy import of Solargis time series data to PVsyst.

For time series data accessed using Web Services it is possible to specify time zone of your choice.

Time stamps

Timestamp for hourly or sub-hourly time series

We use centre of summarization (averaging) interval as default. This means that time intervals 00:00-01:00, 01:00-02:00 .... 22:00-23:00, 23:00-24:00 are represented by timestamps 00:30, 01:30 .... 22:30, 23:30. 
On request, we can also deliver data with timestamp set as end of summarization (averaging) interval. In such case time intervals 00:00-01:00, 01:00-02:00 .... 22:00-23:00, 23:00-24:00 will be represented by timestamps 01:00, 02:00 .... 23:00, 00:00

Exceptions in case of sub-hourly time series

In some instances, data values represent instantaneous values and not summary over a 15 or 30 minute period. This applies in the following scenarios:

i) 15-minute time series data is ordered for locations covered by Meteosat PRIME satellites

ii) 30-minute time series data is ordered for locations covered by Meteosat IODC satellites

In above situations data is represented in the time stamp of satellite data acquisition. For example, timestamps hh:12 and hh:42 would refer to instantaneous values at hh:12 and hh:42.

The type of timestamp used will always be mentioned along with other meta information in the data files delivered.


When I open Solargis data file using Microsoft Excel, all data parameters are showing in one column. How can I separate the data into several columns?

The standard delivery format of Solargis data files is .csv and when you open such file using excel, all data values may be in the first column.

By default, all values should be in numeric format. However, if your computer recognizes ',' or 'comma' as the decimal character instead of '.' some values may appear in date format. In such case, you may want to change the file extension to .txt and then open with excel.

You can then convert all data from the first column to multiple columns using following steps:

  1. Choose the column with all the text and run 'Text to columns wizard' (can be found under Data tab) 
  2. Set Delimited, Next
  3. Select Semicolon, unselect Tab
  4. Select Text as Column Data format
  5. Finish