Being a part of the semi-arid region the analysis of 30 years rainfall data of the Koppal district (Koppal, Kushtagi, Yelburga and Gangavathi taluks) showed that the rainfall pattern followed Gumbel distribution.  The mean annual rainfall and standard deviation for Koppal, Kushtagi, Yelburga and Gangavathi taluks were 634, 567, 568 and 622 mm and 197.5, 180.7, 161.6 and 207 mm, respectively. The Gumbel distribution estimated the probable annual maximum rainfall of 1203.7, 1272.1, 1129.8 and 1332.7 mm for 100-year return period followed by 1093.8, 1138.1, 1032.3 and 1208.9 mm for 50-year return period; 983.2, 1004.1, 934 and 1084.2 mm for 25-year return period; 834, 1004.1, 801.5 and 916.1 mm for 10-year return period; 716.0, 692.8, 696.7 and 783.1 mm for 5-year return period for Koppal, Kushtagi, Yelburga and Gangavathi taluks, respectively. The most probable annual rainfall of 537.7, 515.6, 538.3 and 582.1 mm corresponding to 2-year return period was estimated to be the frequent rainfall in Koppal, Kushtagi, Yelburga and Gangavathi taluks, respectively. The south-west monsoon is highly dependable during September (138.7 mm) and October (148.7 mm), otherwise the low to medium scanty rainfall and higher average temperatures lead to a dry period of more than 150 days, which is a crucial factor in selecting the crops under rainfed agriculture. The analysis of 80 and 95 per cent confidence limits of the estimated values of one-day maximum and annual rainfall at different probabilities indicated that as the confidence probability increased, the confidence interval also increased.