Plot of the median-normalized and outlier-removed PDC sector 2 and 3 light curves of the WASP-18 system. The gaps in the middle of each sector’s time series separate the two physical orbits of the TESS spacecraft contained within the sector. We have removed 30 minutes of data from the start of each orbit’s light curve. The points highlighted in red show severe residual uncorrected systematics in the fits and are removed in the joint analysis presented in this paper. The phase curve variation of the system is clearly visible, as are residual long-term trends in the data. Those trends can include long-term photometric variability of the target or systematics introduced by the instrument and/or analysis.