The Medium Paranapanema region is an agricultural area in the State of São Paulo where minimum air temperatures below 5 ºC (Tmin5) occur during May to September, with little occurrence of frosts. This study aimed to determine the probability of occurrence of Tmin5 which could be harmful to agriculture. Therefore, data of 13 years were analyzed at 7 locations (Assis, Manduri, Tarumã, Palmital, Santa Cruz do Rio Pardo, Quatá and Pedrinhas Paulista) of the region. The analysis of the data was made in two steps; firstly a test was applied to determine if the available data series would be sufficient for the proposed study; and after that, the data were fitted to the Gaussian probability distribution with 10 temperature classes (between 4 and 5 ºC, 3 and 4 ºC, 2 and 3 ºC, 1 and 2 ºC, 0 and 1 ºC, -1 and 0 ºC, -2 and -1 ºC, -3 and -2 ºC, -4 and -3 ºC, -5 and -4 ºC). It was possible to determine that historical series with six years of data were enough for study of the Tmin5. The Gaussian distribution fitting for different temperature ranges and for months were all significant at 5%. Differences of Tmin5 were observed among places and the analyzed months. It was observed that in June and July there is higher probability of Tmin5 in Manduri, Assis and Tarumã. These localities can be considered the coldest of the region. It was also observed that the highest probability for minimum air temperature was about 7% for the whole Medium Paranapanema region in July for temperatures between 0 and 5 ºC.
modeling; climatic risk
