Degree-day estimation in respect to altitude and latitude for São Paulo State

Multiple regression equations were developed to determine the total monthly degree-days in function of altitude (meters) and latitude (minutes), in order to estimate the amount of heat unit for annual crops in localities where meteorological data are not available. The degree-day was determined through thermometric data, using monthly mean values of maximum and minimum temperatures obtained in several meteorological stations of São Paulo State. The base temperature of 10° C, below which great part of the crops does not nave a good development was used to determine the heat-units.