The multitray solar still (MTSS) is one of the most efficient and economical designs compared with other solar still systems. MTSS has lower heat loss and a large evaporation area, and its basin is more exposed to solar radiation. Nevertheless, optimizing the tray's geometry is essential to improve the still's thermal behavior and productivity. The primary goal of this study is to examine the effect of the tray's geometry on the MTSS performance under outdoor experiments. A comparative analysis was conducted between the triangular‐trays solar still (TTSS), the rectangular‐trays solar still (RTSS), and the single‐slope conventional solar still (CSS) in winter and summer weather conditions. Results show that integrating a multitray evaporator improves the daily yield compared with the CSS and that the thermal performance of the modified solar still depends mainly on the weather conditions. The comparison shows that the triangular trays are more effective than the rectangular ones. The daily productivity of TTSS exceeds that of RTSS by 10% in winter and 24.24% in summer. Moreover, the daily thermal efficiencies of CSS, RTSS, and TTSS are maximum in summer conditions by about 28.1%, 41.2%, and 44.15%, respectively.