  We present a catalog of revised effective temperatures for stars observed in
long-cadence mode in the Kepler Input Catalog (KIC). We use SDSS griz filters
tied to the fundamental temperature scale. Polynomials for griz
color-temperature relations are presented, along with correction terms for
surface gravity effects, metallicity, and statistical corrections for binary
companions or blending. We compare our temperature scale to the published
infrared flux method (IRFM) scale for VJKs in both open clusters and the Kepler
fields. We find good agreement overall, with some deviations between (J -
Ks)-based temperatures from the IRFM and both SDSS filter and other diagnostic
IRFM color-temperature relationships above 6000 K. For field dwarfs we find a
mean shift towards hotter temperatures relative to the KIC, of order 215 K, in
the regime where the IRFM scale is well-defined (4000 K to 6500 K). This change
is of comparable magnitude in both color systems and in spectroscopy for stars
with Teff below 6000 K. Systematic differences between temperature estimators
appear for hotter stars, and we define corrections to put the SDSS temperatures
on the IRFM scale for them. When the theoretical dependence on gravity is
accounted for we find a similar temperature scale offset between the
fundamental and KIC scales for giants. We demonstrate that statistical
corrections to color-based temperatures from binaries are significant. Typical
errors, mostly from uncertainties in extinction, are of order 100 K.
Implications for other applications of the KIC are discussed.
