  Using two years of data from the NOvA Near Detector at Fermilab, we report a
seasonal variation of cosmic ray induced multiple-muon event rates which has an
opposite phase to the seasonal variation in the atmospheric temperature. The
strength of the seasonal multipl$ increase as a function of the muon
multiplicity. However, no significant dependence of the strength of the
seasonal variation of the multiple-muon variation is seen as a function of the
muon zenith angle, or the spatial or angular separation between the correlated
muons.
