Method for operating a windshield washing system of a vehicle, the following steps being carried out: - repeatedly initiating a wiping movement of at least one wiper arm on a windshield of the vehicle, in which the wiper arm performs an upward movement from a lower turning point to an upper turning point, and a downward movement from the upper turning point to the lower turning point, - initiating a detergent output for the relevant wiping movement in order to output a detergent during the upward movement from at least one nozzle of the wiper arm, the detergent output having already been initiated during the downward movement in order to apply the detergent to the windshield before the lower turning point is reached, characterized in that, for each of the repetitions of the wiping motion, the following steps are carried out: - deactivating the detergent output for the downward movement after the detergent output has taken place during the upward movement, - already initiating the detergent output during the downward movement, in order to apply the detergent to the windshield during the downward movement, before the lower turning point is reached, and to only wipe this detergent during the subsequent upward movement, and in that a time interval of the relevant wiping movement is measured, and the initiation of the detergent output is carried out depending on the measured time interval in order to output the detergent when a predetermined position of the wiper arm is present during the wiping movement. - repeatedly initiating a wiping movement of at least one wiper arm on a windshield of the vehicle, in which the wiper arm performs an upward movement from a lower turning point to an upper turning point, and a downward movement from the upper turning point to the lower turning point, - initiating a detergent output for the relevant wiping movement in order to output a detergent during the upward movement from at least one nozzle of the wiper arm, the detergent output having already been initiated during the downward movement in order to apply the detergent to the windshield before the lower turning point is reached, characterized in that, for each of the repetitions of the wiping motion, the following steps are carried out: - deactivating the detergent output for the downward movement after the detergent output has taken place during the upward movement, - already initiating the detergent output during the downward movement, in order to apply the detergent to the windshield during the downward movement, before the lower turning point is reached, and to only wipe this detergent during the subsequent upward movement, and in that a time interval of the relevant wiping movement is measured, and the initiation of the detergent output is carried out depending on the measured time interval in order to output the detergent when a predetermined position of the wiper arm is present during the wiping movement. the detergent output having already been initiated during the downward movement in order to apply the detergent to the windshield before the lower turning point is reached, characterized in that, for each of the repetitions of the wiping motion, the following steps are carried out: - deactivating the detergent output for the downward movement after the detergent output has taken place during the upward movement, - already initiating the detergent output during the downward movement, in order to apply the detergent to the windshield during the downward movement, before the lower turning point is reached, and to only wipe this detergent during the subsequent upward movement, - deactivating the detergent output for the downward movement after the detergent output has taken place during the upward movement, - already initiating the detergent output during the downward movement, in order to apply the detergent to the windshield during the downward movement, before the lower turning point is reached, and to only wipe this detergent during the subsequent upward movement, and in that a time interval of the relevant wiping movement is measured, and the initiation of the detergent output is carried out depending on the measured time interval in order to output the detergent when a predetermined position of the wiper arm is present during the wiping movement.