A method comprises measuring a light intensity at a window; determining if the light intensity exceeds a cloudy-day threshold; operating in a sunlight penetration limiting mode to control the motorized window treatment to control the sunlight penetration distance in the space; enabling the sunlight penetration limiting mode if the light intensity is greater than the cloudy-day threshold; and disabling the sunlight penetration limiting mode if the total lighting intensity is less than the cloudy-day threshold. The cloudy-day threshold is maintained at a constant threshold if a calculated solar elevation angle is greater than a predetermined solar elevation angle, and the cloudy-day threshold varies with time if the calculated solar elevation angle is less than the predetermined solar elevation angle. The cloudy-day threshold is a function of the calculated solar elevation angle if the calculated solar elevation angle is less than the predetermined solar elevation angle.