  It was pointed out previously~\cite{Kinney:2014jya} that a sufficiently
negative running of the spectral index of curvature perturbations from
(ordinary i.e. cold) inflation is able to prevent eternal inflation from ever
occurring. Here, we reevaluate those original results, but in the context of
warm inflation, in which a substantial radiation component (produced by the
inflaton) exists throughout the inflationary period.
  We demonstrate that the same general requirements found in the context of
ordinary (cold) inflation also hold true in warm inflation; indeed an even
tinier amount of negative running is sufficient to prevent eternal inflation.
This is particularly pertinent, as models featuring negative running are more
generic in warm inflation scenarios. Finally, the condition for the existence
of eternal inflation in cold inflation -- that the curvature perturbation
amplitude exceed unity on superhorizon scales -- becomes more restrictive in
the case of warm inflation. The curvature perturbations must be even larger,
i.e. even farther out on the potential, away from the part of the potential
where observables, e.g. in the Cosmic Microwave Background, are produced.
