You can try something like below:
format long g
folder = 'BCC_CSM.xlsx';
file = xlsread(folder);
dt = datetime([file(:,1:3) file(:,4)/1E4 repmat([0 0],size(file,1),1)]);
tt = timetable(dt, file(:,5:end));
data = tt.Var1;
% file(:, 3:4) = []; % delete day and hour columns as they are not important for yearly mean
[grps, Years, Months] = findgroups(file(:,1), file(:,2));
result_mean = splitapply(@(x) mean(x, 1), file(:,5:end), grps);
result_mean = [Years Months result_mean];
result_std = splitapply(@(x) std(x, [], 1), file(:,5:end), grps);
result_std = [Years Months result_std];
monthNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
count = 1;
for i = 1:numel(Years)
allMonths{count} = "01-"+monthNames(Months(i))+"-"+num2str(Years(i))+" 00:00:00";
count = count+1;
end
for i = 1:count-2
TR{i} = timerange(allMonths{i},allMonths{i+1});
tt_TR{i} = tt(TR{i},:);
Hs{i} = tt_TR{i}.Var1(:,1);
Tp{i} = tt_TR{i}.Var1(:,2);
%If the above variables TR, tt_TR, Hs & Tp are temporary only then don't use
% cell arrays for them
d_Hs{i} = lognpdf(Hs{i},result_mean(i,3),result_std(1,3));
d_Tp{i} = lognpdf(Tp{i},result_mean(i,4),result_std(1,4));
end
The above code covers the timeranges at the year end like '01-Dec-2026 00:00:00','01-Jan-2027 00:00:00' , If you don't want this timerange then simply use the below code;
Years = ["2026", "2027", "2028"];
Months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
i = 1;
for year = Years
for monthNum = 1:11
TR{i} = timerange("01-"+Months(monthNum)+"-"+year+" 00:00:00","01-"+Months(monthNum+1)+"-"+year+" 00:00:00");
tt_TR{i} = tt(TR{i},:);
Hs{i} = tt_TR{i}.Var1(:,1);
Tp{i} = tt_TR{i}.Var1(:,2);
%If the above variables TR, tt_TR, Hs & Tp are temporary only then don't use
% cell arrays for them
d_Hs{i} = lognpdf(Hs{i},result_mean(i,3),result_std(1,3));
d_Tp{i} = lognpdf(Tp{i},result_mean(i,4),result_std(1,4));
i = i + 1;
end
end
