The measurements of the main weather parameters for tomato crop data were collected in 2002. at experimental meteorological station "E. Pantenelli" of Bari University and CNR-Bari near Policoro (Southern Italy) to investigate the influence of weather and management on crop growth and development parameters which can contribute in difference of Kc values for this climatic region. The results of investigations on Policoro data confirmed relevant difference in the length of the growing period in respect to the data presented in FAO 56. Therefore, careful consideration of all growing and management parameters is needed when crop evapotranspiration has to be estimated under local conditions. This work has shown that peak Kc estimation can be improved by applying the corrections for relative humidity, wind speed and plant height as it suggested in FAO 56. This improvement is particularly important because midseason Kc refers to the peak Kc values and relies on the period of growing season that is usually the most important for irrigation and the most sensitive to water stress, thus when an accurate scheduling should be applied. Overall results indicate that improvments in genetics and crossbreeding techniques, crop management, climatic conditions changes (temperature, relative humidity, wind speed) and irrigation technique have a significant impact on the crop development and crop coefficient values.