Using daily meteorological data of Júlio de Castilhos, Santa Maria and São Gabriel (Brazil) the probable dates of first and last minimum air temperatures equal or lower than -7°C, -6°C, ... and +7°C at 5cm above grass and bare soil were determined. Tables were obtained with the probable occurrence dates of the first and last damaging temperature for several levels of probability. It was observed that as an average, that the probable date of occurrence of the first temperature equal or lower than a certain thermic level for bare soil occurs 6.4 days after occuring at 5cm on grass and 39 before occurring in the meteorological shelter. By other hand, the probable occurence date of the last temperature lower or equal a termic level at 5cm above bare soil occured 10 days before being registred at 5cm on grass and 41 days after being registred in meteorological shelter.
minimum temperature; minimum grass temperature
