This work aimed to verify forecasts of temperature and mineralization of the Lower Jurassic and Lower Cretaceous waters in the Polish Lowlands, based on new geological information. In the first part of the articles series, entitled Verification of geothermal conditions in the Polish Lowlands based on data from new drilling performed in the years 2000–2022, an analysis of geothermal conditions is presented, while this work focuses on hydrogeochemical parameters, such as temperature in the top of formations and water mineralization. For this purpose, data from the Central Geological Database (CBDG), the Central Bank of Hydrogeological Data – HY DRO Bank, and from previously published scientific and research works were used. In the years 2000–2023, twenty-four exploration wells with a depth exceeding 1000 m below ground level were drilled and documented in the Polish Lowlands, providing information on the temperature and mineralization of waters taken from the Lower Jurassic or Lower Cretaceous formations. The assessment of spatial changes, as in the first part of the work, was performed with the use of QGIS Desktop 3.24.1 software, which is geoinformation software (GIS ) that allows viewing, editing, and analyzing spatial data and the creation of maps. The presented analysis made it possible to make a spot, local correction of the projected course of the isoline in relation to the maps published earlier in the Atlas of geothermal resources in the Polish Lowlands. Mesozoic Formations developed in 2006, edited by Wojciech Górecki.