Wind speeds and gusts in Finland: a comparison of observations and ERA5 reanalysis

In this study, we compare hourly wind speed and wind gust observations from 143 weather stations in Finland to ERA5 reanalysis data from 2014–2023. The weather stations are classified into inland, coast, lake, and mountain stations based on their elevation and terrain type. Overall, the correlation between ERA5 and observed winds is strong. However, both the hourly wind speeds and wind gusts in ERA5 are underestimated except for the weakest winds, which are overestimated. The bias is larger in wind speeds than in wind gusts. Among the four station classes, the coast and inland stations have in general the best agreement between ERA5 and observed winds, while ERA5 performance in the mountain stations is relatively poor.