Investigation of air temperature on the nightside of Venus derived from VIRTIS-H on board Venus-Express

► Thermal structure of Venus in the pressure range 100-4 mbar in the night. ► Cold collar feature is located at 60-70° on both hemispheres. ► Thermal structure supports a North-South symmetry. ► Sun-synchronous waves are present at 100, 32, 12, and 4 mbar and confirmed by the LMD Venus GCM model.