Meantime I found a solution. I converted the column values of Results and also the Hour.mean with past function and then I could find the row indices with which function with the following way:
List1 = paste(Results[,1], Results[,2], Results[,3], sep=".")
List2 = paste(Hour.mean[,1], Hour.mean[,2], Hour.mean[,3], sep=".")
ind = which(List1 %in% List2)