This is a non-peer reviewed preprint submitted to EarthArxiv. It is the authors' version initially submitted to Computers and Geosciences corresponding to final paper "Analysis of atmospheric thermodynamics using the R package aiRthermo", published in Computers and Goesciences after substantial changes during the review process with doi: http://doi.parts of the verification code. She performed the analysis of the sounding database presented in the paper and participated in the writing. Gabriel-Ibarra Berastegi collaborated with the verification of results, the testing of the package and the writing of the paper. Highlights 1. A new package providing new functionalities in the field of atmospheric thermodynamics to the R programming language is presented. 2. The most critical functions are written in C to speed up computations. 3. It provides numerical results and Stüve diagrams not previously available in R. 4. A realistic application has been produced for a case-study covering five years of twice-daily soundings over the Iberian Peninsula (2010-2014). 5. The package can be a key part of advanced forecast systems and diagnostics for extreme events (floods, storms, ...).