How to time averaging a net.cdf file

I want to plot mean monthly chlorophyll from daily data. so far i can download the data for a single day and plot it as a pcolor using:

ncfile = 'dataset-global-nahindcast-bio-001-018-V5-chl_1521044729974.nc' ; % nc file name
% To get information about the nc file
ncinfo(ncfile)
% to display nc file
ncdisp(ncfile)
% to read a vriable 'var' exisiting in nc file
chlorophyll = ncread(ncfile,'CHL') ;
lat = ncread(ncfile,'latitude') ;
lon = ncread(ncfile,'longitude') ;
figure (1)
pcolor(lat,lon,chlorophyll)
shading interp
colormap hot
colorbar
grid on 
which works when using a file which has data for a single day, but i would like to know how to average multiple days so that i can download larger files and plot mean monthly chlorophyll instead of daily chlorophyll. I have attached a file with info on the data structure. please let me know if anything else is needed. 

Dimensions: [1×4 struct]
     Variables: [1×7 struct]
    Attributes: [1×15 struct]
        Groups: []
        Format: 'classic'
dimensions:
           x            = 143
           y            = 105
           time_counter = 24
           deptht       = 1

Thanks in advance