  G183$-$35 is an unusual white dwarf that shows an H$\alpha$ line split into
five components, instead of the usual three components seen in strongly
magnetic white dwarfs. Potential explanations for the unusual set of lines
includes a double degenerate system containing two magnetic white dwarfs and/or
rotational modulation of a complex magnetic field structure. Here we present
time-resolved spectroscopy of G183$-$35 obtained at the Gemini Observatory.
These data reveal two sets of absorption lines that appear and disappear over a
period of about 4 hours. We also detect low-level (0.2%) variability in optical
photometry at the same period. We demonstrate that the spectroscopic and
photometric variability can be explained by the presence of spots on the
surface of the white dwarf and a change in the average field strength from
about 4.6 MG to 6.2 MG. The observed variability is clearly due to G183$-$35's
relatively short spin period. However, rotational modulation of a complex
magnetic field by itself cannot explain the changes seen in the central
H$\alpha$ component. An additional source of variability in the line profiles,
most likely due to a chemically inhomogeneous surface composition, is also
needed. We propose further observations of similar objects to test this
scenario.
