CCWeatherGen: Climate Change Weather File Generator for the UK

What is CCWeatherGen?

The climate change weather file generator (CCWeatherGen) enables you to generate climate change weather files for the UK ready for use in building performance simulation programs. It uses the 2002 climate change scenario predictions provided by the UK Climate Impacts Programme (UKCIP) (1). The tool is Microsoft® Excel based and transforms CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs.

The underlying weather file transformation routines of this tool are based on the so-called ‘morphing’ methodology for climate change transformation of TRY/DSY weather files, which was developed by Belcher, Hacker and Powell (2,3). The CCWeatherGen tool includes further calculation routines for parameters that are not originally supplied by TRY/DSY files (such as for example: horizontal infrared sky radiation, daylighting parameters, dew point temperature, humidity parameters, soil temperature). These parameters are required for generating simulation ready TMY2 and EPW files.

The CCWeatherGen tool allows you to generate TMY2 or EPW climate change weather files with a few mouse clicks. You can produce ‘morphed’ climate change as well as ‘unmorphed’ present day TMY2 and EPW files from the original CIBSE/Met Office TRY/DSY format files. The CCWeatherGen tool is made available free of charge. However, it is solely distributed WITHOUT the required baseline weather files and/or climate change scenario data! (Please view sections 2.1 and 2.2 of the CCWeatherGen user manual for information on where to obtain the required baseline data.)

CCWeatherGen is available with an additional tool: the CCWeatherGen Basefile Creator. This tool enables you to generate CIBSE / Met Office style TRY/DSY files from inputted columns of weather data. It is aimed at CCWeatherGen users who possess the CIBSE/Met Office weather data in formats other than that provided directly by CIBSE. Files generated with this tool can be read by CCWeatherGen for further processing into climate change weather data.

Important – please note:
The functionality of this tool is restricted to sites in the UK only. For sites outside the UK please use the CCWorldWeatherGen tool.


Details on the underlying methodology used in CCWeatherGen can be found in the following publication:

  • Jentsch M.F., Bahaj A.S. and James P.A.B. (2008) Climate change future proofing of buildings – Generation and assessment of building simulation weather files. Energy and Buildings,Volume 40, Issue 12, December 2008, pp 2148-2168. view paper

Software Requirements

Basic Requirements for the CCWeatherGen Tool:

  1. A valid installation of Microsoft® Excel on your local hard drive. CCWeatherGen was tested with the 2003, 2007 and 2010 versions. (However, the authors do not take responsibility for any compatibility issues on these or other platforms.)
  2. A licensed copy of a CIBSE / Met-Office TRY and/or DSY file. (see section 2.1 of the CCWeatherGen manual)
  3. A licensed copy of the UKCIP02 climate change scenario data files, which can be downloaded free of charge. (see section 2.2 of the CCWeatherGen manual)

Download CCWeatherGen V 1.1.2 and associated manuals

CCWeatherGen is provided as a self-extracting file within a zip file. Please click the link below, unzip the file, run the executable and follow the instructions on the screen.

All instructions required for operating CCWeatherGen are given in the user manual. It is highly recommended to read the manual before using the tool. A separate help file is provided for the CCWeatherGen Basefile Creator.

The calculation routines underlying the CCWeatherGen and CCWorldWeatherGen tools are detailed in a technical reference manual:

Copyright and Licensing Notes

The original TRY/DSY weather files used for generating climate change weather files with the CCWeatherGen tool are copyrighted material from CIBSE / Met Office. Therefore, generated weather files can only be used by persons or entities who possess the corresponding licensed CIBSE / Met Office weather files. The user of the CCWeatherGen tool takes the sole responsibility of complying with the terms and conditions of the ‘CIBSE / Met Office Weather Data Licence Agreement’. TRY/DSY data/licenses can be purchased from the CIBSE bookshop. Furthermore, the user of the CCWeatherGen tool takes the sole responsibility of complying with the terms and conditions of the ‘License Agreement of the UKCIP02 Climate Scenarios Dataset’ which is available on the UKCIP data archive website.

Disclaimer of Warranties

The entire risk as to the quality, accuracy and performance of the climate change weather data calculated with the CCWeatherGen tool is with you. In no event will the authors of the weather file generation tool be liable to you for any damages, including without limitation any lost profits, lost savings, or other incidental or consequential damages arising out of the use or inability to use the tool and/or its generated data.


The authors of the CCWeatherGen tool gratefully acknowledge the UKCIP02 climate change scenario data by the UK Climate Impacts Programme (UKCIP) (1) which is required for this tool and is available from the Environment Agency Climate Ready Helpdesk. (© Crown Copyright 2002. The UKCIP02 Climate Scenario data have been made available by the Department for Environment, Food and Rural Affairs (DEFRA). DEFRA accepts no responsibility for any inaccuracies or omissions in the data nor for any loss or damage directly or indirectly caused to any person or body by reason of, or arising out of any use of, this data.)

The TRY/DSY weather file morphing methodology for generating climate change weather data developed by Belcher, Hacker and Powell (2,3) which formed the basis for this weather file generator tool is gratefully acknowledged. Special thanks go to Linda Lawrie and Drury Crawley for providing guidance on the appropriate ground temperature equations for generating EPW files. Furthermore the work of the following people / institutions that was key to compiling this weather file generator tool is also gratefully acknowledged: the ASHRAE psychrometric formulae (4), the TMY2 weather file manual by Marion and Urban (5), the EPW weather data description by Crawley, Hand and Lawrie (6), the all sky model for calculating downwelling longwave radiation by Crawford and Duchon (7), the models for calculating illuminance and sky luminance parameters from radiation data by Perez, Ineichen, Seals, Michalsky and Stewart (8), the Meteonorm weather software version 6.0 which was used to generate average monthly global horizontal radiation baseline data for the CIBSE/Met Office weather sites (9), the ground temperature equation by Kusuda and Achenbach (10), the paper on TRY / DSY file generation by Levermore and Parkinson (11), the optical air mass tables provided by Kasten and Young which were used for calculating illuminance and sky luminance parameters (12) and CIBSE Guide J which was used for calculating direct normal solar radiation (13).

The self extracting download file was generated using FreeExtractor v1.44.

Aspects of this work were undertaken within the Sustainable Urban Environment (SUE) programme funded by the UK Government Engineering and Physical Sciences Research Council (EPSRC). Project: Innovation in Design, Construction & Operation of Buildings for People (IDCOP), Partners: ARUP, University of Greenwich, University of Reading, University of Southampton.


  1. Hulme M, Jenkins GJ, Lu X, Turnpenny JR, Mitchell TD, Jones RG, Lowe J, Murphy JM, Hassell D, Boorman P, McDonald R, Hill S. Climate Change Scenarios for the United Kingdom: The UKCIP02 Scientific Report. Norwich, UK: Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia, 2002.
  2. Belcher SE, Hacker JN, Powell DS. Constructing design weather data for future climates. Building Services Engineering Research and Technology 2005; 26 (1): 49-61.
  3. CIBSE. Climate change and the indoor environment: impacts and adaptation, CIBSE TM36, London: The Chartered Institution of Building Services Engineers, 2005.
  4. ASHRAE. Chapter 6 – Psychrometrics. ASHRAE Handbook – Fundamentals. Atlanta: American Society of Heating Refrigerating and Air-Conditioning Engineers, 2005.
  5. Marion W, Urban K. User’s Manual for TMY2s – Typical Meteorological Years. Golden, Colorado, USA: National Renewable Energy Laboratory 1995.
  6. Crawley DB, Hand JW, Lawrie LK. Improving the weather information available to simulation programs. Building Simulation ‘99 Conference. Kyoto,
    Japan; 1999.
  7. Crawford TM, Duchon CE. An improved parameterization for estimating effective atmospheric emissivity for use in calculating daytime downwelling longwave radiation. Journal of Applied Meteorology 1999; 38 (4): 474-480.
  8. Perez R, Ineichen P, Seals R, Michalsky J, Stewart R. Modelling Daylight Availability and Irradiance Components from Direct and Global Irradiance. Solar Energy 1990; 44 (5): 271-289.
  9. Meteonorm 6.0. Meteotest.
  10. Kusuda T, Achenbach PR. Earth temperature and thermal diffusivity at selected stations in the United States. ASHRAE Transactions 1965; 71 (1): 61-74.
  11. Levermore GJ, Parkinson JB. Analyses and algorithms for new Test Reference Years and Design Summer Years for the UK. Building Services Engineering Research and Technology 2006; 27 (4): 311-325.
  12. Kasten F, Young AT. Revised optical air mass tables and approximation formula. Applied Optics 1989; 28 (22): 4735-4738.
  13. CIBSE. CIBSE Guide J – Weather, solar and illuminance data. London: The Chartered Institution of Building Services Engineers, 2002.