This study’s aim is to appreciate real site surface temperature error values obtained using a thermocouple on semi-transparent materials and to determine a method of correction. Using an efficient measurement system, an experimental study was carried out under a number of climatic conditions. The results show that high values for solar radiation and wind speed have a significant influence on thermocouple measurement. The authors, therefore, decided to validate and develop a corrective model for the measurement errors of these two parameters. The conclusion also provides data on the model’s relative drawbacks and current limitations.