annual, seasonal mean from monthly time series

I have a monthly mean time series netcdf data.

I want to get annual and seasonal mean (4 seasons). Here is my code, but I am not really able to get what I want.

MySeas = {'JJA','SON','DJF', 'MAM', 'ANNUAL'};
s = size(tERA); % data starts from 09 2008 til 08 2012
% s = 237    77    12    48

for ss=1:length(MySeas)
    curSeas = MySeas{ss};
    switch curSeas 
        case {'Annual'} % mean of 09 to 08 of each year, 12 months 
            tANNx = squeeze(mean(reshape(tERA,[s(1:3),12,s(4)/12]),4)); % size: 237,77,12,4
            tANN = mean(tANNx,4);            
        case {'JJA'} %mean of 06, 07, 08 of each year
            tJJAx = squeeze(mean(reshape(tERA,[s(1:3),3,s(4)/12]),4)); % size: 237,77,12,4
            tJJA = mean(tJJAx,4);
        case {'SON'} % mean of 09, 10, 11 of each year
            tSONx = squeeze(mean(reshape(tERA,[s(1:3),3,s(3)/12]),4)); % size: 237,77,12,4
            tSON = mean(tSONx,4);
        case {'DJF'} %mean of 12, 01, 02 of each year
            tDJFx = squeeze(mean(reshape(tERA,[s(1:3),3,s(3)/12]),4)); % size: 237,77,12,4
            tDJF = mean(tDJFx,4);
        case {'MAM'} %mean of 03, 04, 05 of each year
            tMAMx = squeeze(mean(reshape(tERA,[s(1:3),3,s(3)/12]),4)); % size: 237,77,12,4
            tMAM = mean(tMAMx,4);
        otherwise
            txt='not applicable: ';
    end
end
           

Please correct the squeeze statements. Thank you.

Answer 1

[Cris LaPierre]

I don't know much about your data, but I would see if groupsummary works. If you have datetime info in your data, you can use the 'groupbin' input to specify a way to automatically group your data and then apply method(s) to each group.

G = groupsummary(T,groupvars,groupbins,method,datavars)

Answer 2

[Steven Lord]

Consider using groupsummary with the season data as your grouping variable.