The modelling system GRAMM/GRAL is developed and maintained by the Technische Universität Graz (Austria)and the Air Quality Control office of the government of Styria (Austria). All codes are available at: lampx.tugraz.at/ gral/index.php. A python library was developed to use GRAMM/GRAL in a so-called match-to-observation mode. That is to say, a catalogue of reference simulations is matched with actual observations to deduce a sequence of weather situations. The procedure is fully described and evaluated in the two following publications: - Antoine Berchet, Katrin Zink, Clive Muller, Dietmar Oettl, Juerg Brunner, Lukas Emmenegger, Dominik Brunner, A cost-effective method for simulating city-wide air flow and pollutant dispersion at building resolving scale, Atmospheric Environment, Volume 158, June 2017, Pages 181-196, ISSN 1352-2310, http://doi.org/10.1016/j.atmosenv.2017.03.030. - Berchet, A., Zink, K., Oettl, D., Brunner, J., Emmenegger, L., and Brunner, D.: Evaluation of high-resolution GRAMM/GRAL NOx simulations over the city of Zurich, Switzerland, Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2017-102, in review, 2017.