UK-wide Typical Meteorological Year Global Horizontal Irradiance Data for Photovoltaic Systems

2018-08-08T14:22:09Z (GMT) by Diane Palmer Tom Betts


The data available for download comprises hourly TMY Global Horizontal Irradiance values generated from the 2008-2016 decade for a 10 x 10 km resolution grid covering the UK and Northern Ireland. Global Horizontal Irradiance in Wh/m^2.

The data is initially interpolated to each grid point from UK Meteorological Office measured values. The TMY for each point is calculated as follows:

  1. For each month in the year (i.e., Jan., Feb., March, etc.), the ten-year monthly mean of irradiance data is obtained for the period 2004-2015.

  2. The historic month that most closely matches the ten-year mean for that month is identified i.e. the most “typical” month.

  3. The hourly data values from the twelve typical months are combined to create the typical year file. This might comprise e.g. January from 2010, February from 2005, March from 2007 etc.

This simple method has been shown to perform well compared to other free-to-download TMY datasets.

If you make use of this data, please:

1. E-mail with details of your employer/institution and a brief description of the project for which you require the data.

2. Cite this journal paper in any publications: /


Open the kml file in Google Earth or software of your choice and locate the grid point nearest to the location you are interested in. Look up the coordinates of the point in the grid info file. Unzip folder and use Windows Explorer to open the csv containing TMY data for your selected point.

Please note that the KML file is released under a CC BY-SA licence as described in the file.