Most countries have a national weather station. In Côte d’Ivoire, it is the Aeronautical and Meteorological Exploitation Company (SODEXAM) which is in charge of it through its databank. The inaccessibility of these data leads many solar energy entrepreneurs to move toward free sites that are often out of phase with the meteorological realities of the area considered. We propose in this paper, a comparative study of two sunshine measurement techniques, namely, the technique of the heliograph and that of the thermoelectric pyranometer, to discuss the reliability of the data provided by these techniques, but also to analyze the seasonal variations of the insolation of Abidjan from 1978 to 2017. The comparison of the results produced by these two approaches showed a discrepancy of up to 43%, with much higher values for the national station. The analysis of the solar field of this city over a period of 19 years has shown a great variability of the solar energy potential which starts from a decrease in energy, from 4447 Wh/m2 (1978–1988) to 3303 Wh/m2 (2003–2009), to achieve an energy increase up to 4782 Wh/m2 (2016–2017). The solar year has been characterized in three solar seasons depending on the mensuel solar irradiation.