This study is based on a 50-year data series (1964-2013) of total solar radiation (G) from the Kołobrzeg - station that is located on the Polish Baltic Sea coast and is characterised by a very high level of air quality. To find and remove gross errors, quality control checking procedures were applied in this study. Additionally, the homogeneity of the G series in this study has been tested on a monthly basis by using of the Standard Normal Homogeneity Test for single shifts. We found a statistically non-significant decrease in G during the period from 1964 to 2013. The decrease in the 5-year mean total solar radiation is evident from the beginning of the 1980s, with the minimum mean value occurring in the second half of the 1990s, while G slightly increased from the early 2000s. The analysis of seasonal G patterns shows that total solar radiation in summer is the most similar to the annual pattern and only the summer series trend shows a statistically significant decrease in G. We also have found two noticeable tendencies in monthly anomalies of G over the studied decades; they are negative trends in May and August. The shape of the decadal daily G histogram remained unchanged during the analysed decades.