Abstract The article describes an experimental investigation of the impact of soiling on the photovoltaic modules in northeastern, Iraq. Over five months, the voltage, current power and energy curves of two identical modules with varying cleaning strategies (one was naturally dusty while the other was cleaned regularly) were measured. The impact of soiling on the daily energy produced as well as rain accumulation and particulate matter concentrations are discussed. The results indicated that no losses occurred during wet seasons, but a considerable decline in performance was found during dry periods owing to soiling. Additionally, it was discovered that soiling has a bigger effect on the maximum power than the short-circuit current. After two dry summer months, the greatest power loss of up to 22% was seen. The daily energy loss due to soiling was determined to be 16% on average. Furthermore, there are four polynomial models that have been drowned in prediction photovoltaic module (voltage, current, power, and energy) degradation due to the accumulation of dust.