The Dead Sea basin is the lowest terrestrial site on the globe and is internationally recognized as a photoclimatotherapy center. Since the last century, questions raised regarding the possible presence of a unique incident ultraviolet irradiation, allowing successful treatment of psoriasis, atopic dermatitis and other dermatological diseases. Aim: Determine the characteristics of the solar ultraviolet irradiation and understand the mechanism of action of photoclimatotherapy while applying the results to clinical protocols of treatment. Methods: A meteorological station was established at the Dead Sea basin to continuously measure global, UVB and UVA irradiation. The same irradiation parameters are also being monitored continuously by a set of identical ultraviolet irradiation instruments installed on the campus of the Ben-Gurion University of the Negev, in Beer Sheva. Results: This study details the results of these long-term measurements, ae well as their correlation with the success obtained by clinicians treating psoriasis patients. Conclusions: A database of more than 25 years has enabled the medical staff to establish tailor-made protocols for sun-exposure time intervals as a function of particular month and hour of day. The availability of such information has significantly improved the results of photoclimatotherapy for psoriasis and at the same time increasing the safety of sun-exposure at the Dead Sea.