Morning is not a separate time of day for evolution.

As far as evolution is concerned, it's always day or night--there is no
in-between period when Eevee will not evolve into Espeon or Umbreon, and
there are no Pokémon that only evolve during the early part of the day.
Having 'morning' as a separate value is thus misleading, albeit not
terribly misleading since it never appeared outside of tables.py.