In the paper we described the main features of ISATIS system, data organisation and modelling workflow. We introduced an approach to modelling July average air temperature and July average precipitation totals in Slovakia by means of ISATIS capabilities. Ordinary kriging and external drift kriging were used to produce surfaces of these variables. The elevation was used as the predictor variable in the latter method. The accuracy of developed models was evaluated by comparing true vs. estimated values, as produced by the crossvalidation procedure. As was expected, supporting the calculation by elevation data reduced the amount of uncertainty in the models and errors of both variables were lower in this case. The final maps are given in the paper as well.