Data analysis and interpretation has always played a fundamental role in the scientific curricula of high school students. The spread of digitalization has further increased the number of learning environments whereby this topic can be effectively taught: as a matter of fact, the ever-growing diffusion of data science across diverse sectors of academic research and economy has profoundly affected the orientation of the educational systems in many countries. In addition to this, the number and effectiveness of learning activities using data analysis and interpretation have been considerably enhanced by the diffuse availability of open data. In this paper, we propose a learning activity to introduce high school students to data analysis and interpretation; the aim is to detect the presence of atmospheric thermal tides starting from the analysis of surface pressure data obtained from open data sets available online. The activity is focused on three main educational goals: (1) Pedagogical goal: developing a stronger awareness of the importance of scientific data literacy; (2) Citizenship goal: fostering the access to free open data resources, hosted by national and international institutions; and (3) Learning goal: contributing to the acquisition of the basic skills to analyze experimental data, with particular regard to the time series analysis of environmental data.