## 3 Results and Discussion
### Sky Characteristics and Photopic Descriptions  
The outdoor solar conditions of the study during the experiment were registered (Table 1), and the SPDs were measured (Figure 1). The highest irradiances can be found in the east direction at 30\({}^{\circ}\)-45\({}^{\circ}\) in practically every month except in December, January and October. In those three months, at 15\({}^{\circ}\), the irradiance is higher than that at 45\({}^{\circ}\). This is followed by the south direction, except in January and November. In those two months, at 15\({}^{\circ}\), the irradiance is higher than at 45\({}^{\circ}\). The lowest irradiances are in the west orientation except in five months (February, March, September, October and November), which slightly exceed the values in the north direction (Table 1 and Figure 2). From April to September, the sun is located in the east and at the highest latitudes (Table 1 and Figure 2). In the normalized SPD curves (Figure 1), spectral variations were found throughout the months of the year and depended on the cardinal points at which the measurements were taken. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**NORTH**} & \multicolumn{3}{c}{**EAST**} & \multicolumn{3}{c}{**SOUTH**} & \multicolumn{3}{c}{**WEST**} \\ \hline  & \(\mathbf{15^{\circ}}\) & \(\mathbf{30^{\circ}}\) & \(\mathbf{45^{\circ}}\) & \(\mathbf{15^{\circ}}\) & \(\mathbf{30^{\circ}}\) & \(  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**NORTH**} & \multicolumn{4}{c}{**EAST**} & \multicolumn{4}{c}{**SOUTH**} & \multicolumn{4}{c}{**WEST**} \\ \hline  & **15\({}^{\circ}\)** & **30\({}^{\circ}\)** & **45\({}^{\circ}\)** & **15\({}^{\circ}\)** & **30\({}^{\circ}\)** & **  
Figure 1: Normalized spectral power distribution depending on the orientation (north, east, south, and west), elevation (\(15^{\circ}\), \(30^{\circ}\), and \(45^{\circ}\)) and seasonality. In most of the data, higher CCTs were found in the north and west orientations than in the east and south orientations and in the winter months (from December to March) and some of the autumn months, especially in October (Figure 3). In general, the CCTs are higher in measurements taken at 45\({}^{\circ}\) and lower in those taken at 15\({}^{\circ}\). The average CCT was 6122 K; the maximum value was taken in March, facing north at 45\({}^{\circ}\) (12,380 K); and the minimum was taken in December, facing south at 15\({}^{\circ}\) (4892 K). In general, the CCTs where the sun is located (south and east) always comprised warmer restricted ranges irrespective of the season and the sky altitude. Conversely, in the opposite locations (north and west), the CCTs are altitude-dependent; and the higher the CCT is, the cooler the results that are  
Figure 2: Irradiances from 380 to 780 nm (\(\mu\)W/cm\({}^{2}\)) measured depending on the season (from December 2018 to November 2019); orientation of north (**top**), east (**right**), south (**bottom**), and west (**left**); and elevation from the horizontal level of 15\({}^{\circ}\) (black), 30\({}^{\circ}\) (striped), and 45\({}^{\circ}\) (grey). found. The measured CCTs show variations as a function of the season, orientation and altitude in correspondence with CIE D illuminances, even with clear sky conditions [22; 23]. When the value of the sky is considered, daylight approaches 6500 K. The average value of the data taken in this study is 6122 K, similar to the dominant CCT of the study conducted in the city of Granada, Spain (5700 K). However, the recorded data show there were variations throughout the year, which highlights the importance of studying the parameters of the daylight in each type of sky and in different climatic conditions [24]. Although the CCT measurement gives us information mainly on the appearance of colour and on aesthetic perception, its influence on circadian effects can also be considered. Our experiment was performed in an urban environment, and it did not consider either the level or the components of the atmosphere.