Brightness temperatures inferred for the dayside (left panel) and nightside (right panel) of WASP-121 b, shown at the top. Offsets of the phase-curve maxima relative to conjunction (left panel), and planet-to-star radii ratios (right panel), shown at the bottom. Parameters obtained from the Spitzer/IRAC data are represented with blue and red squares for channel 1 and 2, respectively. Those obtained from the JWST/NIRSpec G395H data are represented with blue and red triangles for NRS1 and NRS2, respectively.