  We investigate changes in Earth's atmospheric models coming from the $f(R,T)$
modified theory of gravity, in which the gravitational Lagrangian is given by
an arbitrary function of the Ricci scalar and the trace of the stress-energy
tensor. We obtain a generic form for the gravitational field equations and
derive the hydrostatic equation for Earth's atmosphere for leading order terms
$f(R,T) = R + 2\chi T.$ Based on the apparent accuracy of the 1976 U.S.
Standard Atmosphere model, which varies no more than $10\%$ from observations,
we find limits of $-1.6\times 10^{-13} \lesssim \chi \lesssim 1.8\times
10^{-13}$.
