The behavior of temperate climate fruit crops in the State of São Paulo - Brazil as function of "dormancy units" (DAMARIO, 1969) was analysed with the object of providing a simple method for mapping areas with aptitude for commercial development of the crop trees. Thermographs from 12 agrometeorological stations located at altitudes varying from 25 to 1000 meters above sea level and corresponding to the period 1964-1973 were analysed. The number of hours with temperatures below 7 and 13°C, obtained from the diagrams, were correlated with the mean temperature of July, the coldest month, with correlation coeficients equal to -0.88 and -0.93, respectively. Regression equations, were used for mapping the isolines of "dormancy units" for both base temperatures. It was shown that the total period with temperature below 7°C is variable from 20 to more than 200 hours as the altitude increases. A good agreement between commercial exploitation of the crops and the chilling period was also observed.