Find minimum value in every nth rows

I have a cell array( see attachment) of 2209x6. The data is hourly and I want to find the smallest value in column 4(SZA) for everyday. Then create a new array with that row and all the columns.

Answer 1

[Andrei Bobrov]

a = CP15OND_SZA(2:end,4);
a(cellfun(@isempty,a)) = {nan};
a = [a{:}]';
[aout,ii]= min(reshape(a,24,[]));
C = CP15OND_SZA(2:end,:);
out = C(ii+(0:24:numel(a)-1),:);