Teesta River basin, located in the northwest of Bangladesh, is more vulnerable to floods if compared to other parts of the country. In this context, daily rainfall data of ten raingauge stations located in the catchment of the Jamuneswari River, part of the Teesta River basin, were analysed to study the impact of climate change on rainfall. Length of wet and dry series and mean monthly rainfalls along with their variances were used for validating Long Ashton Research Station Weather Generator (LARS-WG). The analysis was carried out for A1B, A2 and B1 emission scenarios using 15 Global Climate Models GCMs simulations for the periods 2011–2030 centred at 2020, 2046–2065 centred at 2055 and 2080–2099 centred at 2090. The analysis of the data shows that the uncertainty in the prediction increases with the timescale. It was also found that the variability in the predictions is smaller in annual values followed by seasonal. Ensemble of seasonal analysis shows that most of the GCM are in agreement for changes in monsoon season. The LARS-WG has reasonable skill to downscale the point rainfall data and the results obtained so are useful to analyse the impact of climate change on the hydrology of the basin.