Upper panel: evolution of W1 − W2. The red dashed line denotes the mean level of the last five epochs. Middle panel: the dust temperature evolution of AT 2019qiz. The red, blue, and green solid lines denote the temperature of astronomical Si, Gra, and SiC, respectively. The dashed lines denote the mean values of the last five epochs. Lower panel: the OUV and IR luminosity evolution of AT 2019qiz. The orange dots denote the OUV blackbody luminosity generated from ZTF and Swift/UVOT data. The red, green, and blue dots denote the IR luminosity assuming dust with a radius of 0.1 μm composed of Si, SiC, and Gra, respectively. The rest-frame days since peak are relative to the date of the optical flare peak (MJD ∼ 58767.61).