I assume the temperatures in B exactly match those in A? In other words, you are not interpolating. First the FOR loop you request:
% Sample data.
A = [(1:20).',sort(round(rand(20,1)*1000)/100)]
B = [5;6;12]
% Fill C.
C = zeros(size(B));
for ii = 1:length(B)
C(ii) = A(A==B(ii),2);
end
But now look at an easier way:
C = interp1(A(:,1),A(:,2),B)
