Gamma distribution models have been considered for modelling rainfall amounts on a monthly and seasonal basis. Generalized linear models can be employed to fit these models. The daily rainfall data at Chingombe Mission (Zambia) have been analysed. The seasonal pattern has bee summarized by fitting a smooth curve. Thus for each day of the season, the mean amount of rain per rainy day can be computed using the estimates of the parameters of the model. A new technique has been introduced to check the adequacy of the fitted model, using the deviance residuals.