  The ESA/Gaia mission is providing accurate and precise all-sky photometry. We
combined effective temperatures derived, for a sample of dwarf and giant stars,
by Gonzalez Hernandez \& Bonifacio (2009) using the Infrared Flux Method, with
the photometry available from the second release of the ESA/Gaia mission. We
provide colour-temperature relations for the broad-band colours (BP-RP),
(BP-G), (G-RP), (G-K), (BP-K), (RP-K). These relations allow the exploitation
of the all-sky Gaia DR2 photometry to obtain precise effective temperatures.
