This study was carried out to estimate the dailly hours number to dry seeds with
forced ambiental air in Pelotas county, RS, Brazil. Were used Relative Moisture (RM) and
Temperature (T) dailly data means, obtained at Pelotas Agroclimatological Station (latitude 31°52?S,
longitude 47°00?W and 13m altitude) searched between the years 1931 and 1990. The variables
used were the dailly mean relative moissture and temperature, after the estimation of RM and T
values, day by day, the following parameters were determinated: 1) Diural and nocturnal hours
number with RM ≤70%; 2) Diural and nocturnal hours number with T ≥10°C; 3) Diural and
nocturnal hours number with RM ≤70% and T ≥10°C. It was considerated diurnal the period
between 6:00 AM and 18:00 PM. The results show that drying seeds with forced ambiental air is
viable process to dry seeds in Pelotas, during the months of november to april. The best period to
dry seeds in Pelotas goes from the third decennial of november to the second decennial of
january.