Hello, everyone. Is it possible that there is a big difference in weather data between three locations in one city? I need to use the weather data of Harbin, China. There are three stations (509530_IWEC, 509530_CSWD, and 509530_SWERA). I compared their monthly direct normal radiation. The results are quite different, especially the trends are different.The data for CSWD looks normal to me. It is strange that for IWEC, there is a peak in March and the minimal value appears in July.

Harbin-IWEC-montly direct norma radiation (Wh/m2-day) Jan: 145; Feb: 184; Mar: 210; Apr: 174; May: 153; Jun: 151; Jul: 105; Aug: 131; Sep: 136; Oct: 148; Nov: 121; Dec: 107.

Harbin-CSWD-montly direct norma radiation (Wh/m2-day) Jan: 74; Feb: 89; Mar: 174; Apr: 163; May: 210; Jun: 240; Jul: 208; Aug: 178; Sep: 146; Oct: 123; Nov: 97; Dec: 69.

Harbin-SWERA-montly direct norma radiation (Wh/m2-day) Jan: 114; Feb: 124; Mar: 147; Apr: 144; May: 161; Jun: 165; Jul: 149; Aug: 179; Sep: 189; Oct: 181; Nov: 128; Dec: 102.

Does anyone know the possible reason for this difference? Thanks in advance.