Particle deposition onto the surfaces of solar energy conversion technologies leads to effective energy output losses. This study shows a full year of measurements using a semi-automatic apparatus, from Kintech Engineering, Spain, based on short-circuit measurements of two PV modules. Annual trends are shown and compared to older studies for the same region, as well as, seasonal behavior. Soiling rates, the soiling ratio variation overtime, is calculated for the driest season of the year, showing results between 0.07% and 0.14% per day, demonstrating a certain constancy regarding other studies. Rainfall, the main natural cleaning agent, is also related to soiling recovering showing that a value around 2.2 mm has 50% chance to reduce the Soiling Ratio. (C) 2020 Elsevier Ltd. All rights reserved.