The paper presents a graphical technique for the rapid analysis of the complex, nonlinear equation that describes the variation of the production temperature of a horizontally-fractured geothermal well. The nomogram presented for the evaluation of the production temperature incorporates the mass flow rate, fracture width, fracture length, number of conductive fractures, host rock temperature, and the production time. The range of the fracture length considered in the nomogram varies from 100 m to 1000 m whereas host rock temperature can be selected from a range of 100 o C to 260 o C. The production temperature predicted by the nomogram agrees well with the analytical solution. The most attractive feature of the proposed technique is its extreme simplicity and speed of operation.