  Here we analyze the Hawking radiation detected by an inertial observer in an
arbitrary position in a Reissner-Nordstr\"om spacetime, with special emphasis
on the asymptotic behavior of the Hawking spectrum as an observer approaches
the inner or outer horizon. Two different methods are used to analyze the
Hawking flux: first, we calculate an effective temperature quantifying the rate
of exponential redshift experienced by an observer from an emitter's vacuum
modes, which reproduces the Hawking effect provided the redshift is
sufficiently adiabatic. Second, we compute the full Bogoliubov graybody
spectrum observed in the three regimes where the wave equation can be solved
analytically (at infinity and at the outer and inner horizons). We find that
for an observer at the event horizon, the effective Hawking temperature is
finite and becomes negative when $(Q/M)^2>8/9$, while at the inner horizon, the
effective temperature is always negative and infinite in every direction the
observer looks, coinciding with an ultraviolet-divergent spectrum.
