Absolute color magnitude diagram of Y dwarfs with available measurements in the Y-band filter from Leggett et al. (2013). A color shift was not applied to account for differences in the pass-band from Gemini-NIRI data to VLT-HAWK-I data; distances were taken from Leggett et al. (2013) and Beichman et al. (2014). The arrow at the bottom right shows the upper limit presented in this work, making WISE0855 the reddest BD. The stars show the individual components of the tentative Y2 binary (WISEPCJ1828+2650), proposed to explain the over-luminosity in the mid infrared. Colored points shows two of the models from Morley et al. (2014), with 50% cloud coverage, a sedimentation factor f_sed = 5, and log g = 3 and 5, connected with black dashed and solid line for clarity.