My Physics books indicate that wavelengths greater than 610 nm are 'red'.

To the original 'Glare' question:

Glare is a scattered reflection of source light. It's wavelength/color
is a function of the color temperature of the source, or the color
spectrum of the source as in solar, and the absorption coefficient[s] of
the reflecting material[s] at the wavelength or over the spectrum of the
source.

So, in general terms, the color of glare has the primary color of the
source and a second component based on the absorption cross section
[color] of the glare producing material.

In simple terms, glare contains two or more spectral responses that may
be line sources, or spectral sources and line reflections from 'pure'
material or spectral sources from compound materials.

Potentially, glare can contain the entire visible spectrum. [400 nm to
approximately 700 nm]

At RF, HF, VHF, UHF, SHF, etc. the parallel to glare is scattering from a
reflective surface where the line spectral response is the single frequency.
And reflection of spectral powwer density is scattered background noise;
like from BPL :-)

Deacon Dave