It can be assumed that the atmospheric conditions in Poland are optimal, because, contrary to popular belief, hot regions of the world and prolonged heat are not conducive to energy production from photovoltaics. The temperature of the module during its operation is inversely proportional to its efficiency. Its influence on the operation of the installation is significant; therefore, a value of 25 \({}^{\circ}\)C, calculated as the most suitable, is given for the rated conditions (Normal Operating Cell Temperature and Standard Test Conditions). Each photovoltaic module manufacturer should declare the value of such parameters as temperature and power factor. It is defined as the value by which the efficiency will change when the cell temperature changes by 1 \({}^{\circ}\)C [16]. From the formula presented by [PERSON], [PERSON], and [PERSON], it can be seen that the module temperature depends on many factors related to the prevailing conditions ( irradiance and ambient temperature) and the properties of the materials the photovoltaic module is made of (module efficiency, power temperature coefficient, absorbance, and transmittance) [17; 18; 19]. In order to determine the module temperature even more precisely, it is necessary to take into account the heat released when current flows through the semiconductor region and, if wind is present, the heat transfer in forced convection [20]. Although the resistance value in semiconductors decreases with increasing temperature, the efficiency of the cell decreases. In most electrical devices, resistance is responsible for most of the losses in the flow of electricity. This is not the case with photovoltaic cells. The main source of energy loss is the decrease in the mobility of electrons and holes as the temperature of semiconductors increases under the influence of voltage forcing. In the case of monocrystalline cells, the production process involves, among other things, the purification of the material to a silicon content of 99%. Particularly visible mobility changes occur with a low dopant content in crystalline silicon. However, they are added to the semiconductor p layer to separate the positive (p) and negative (n) junction layers. A junction containing dopants (e.g., Al or B) has one of the covalent bonds decomposed. This causes the formation of holes and, under the influence of incident photons on the n junction, the appearance of a potential difference and current flow [8]. This is the main reason for the decrease in cell efficiency for operation above 25 \({}^{\circ}\)C. If the module temperature drops below the rated conditions, the instantaneous efficiency may exceed the rated efficiency (provided that the other parameters included in the STC remain constant). This can occur in winter when the temperature drops below 0 \({}^{\circ}\)C or during adequate cloud cover because part of solar radiation is reflected and falls into the photovoltaic panel. Usually, the state of higher efficiency lasts no longer than 1 h.  
Most of the studies conducted from 1991 to 2016 focused only on some factors related to PV panels. In addition, these studies did not reveal the direct quantitative impact of each factor on panel performance but rather focused more on showing the overall increase or decrease in the impact of certain factors, both environment-related and internal factors [21; 22]. Mathematical models can be used for local sunshine forecasting [23]. Research carried out in Portugal has made it possible to generate improved insolation maps. The release of the results had an impact on the future planning of photovoltaic farms, among other things [24]. It is also possible to use neural networks for global insolation forecasting. One model considered meteorological data from several variables: mean daily air temperature, insolation, evaporation, and wind speed [25]. Similar results were obtained from the model by [PERSON] and [PERSON] [26]. However, they are valuable as they take into account climatological variables generating negligible errors of 5-7.5% for different areas.