Longitudinally resolved effective temperature estimates of LTT 9779 b using the GP outlined in E. K. Pass et al. (2019). Blue: effective temperatures estimated with the NIRSpec/G395H phase curve. We report the dayside and nightside temperatures based on the full-resolution data, prior to any binning. Green: effective temperature estimates with binned NIRSpec/G395H data. We divided the phase curve into six equal-width bins of 30° in orbital phase, centered at evenly spaced phases. For each bin and wavelength, the flux was taken as the arithmetic mean of all measurements within the bin. Lower and upper uncertainties were propagated by combining the individual errors in quadrature and scaling by the number of points in the bin. Red: effective temperature estimates with the combined NIRSpec+NIRISS phase curve. Temperatures are calculated by combining the binned NIRSpec and median-fit NIRISS flux measurements. Near the equator, the unbinned NIRSpec and NIRSpec+NIRISS effective temperatures overlap.