Not by the color that you see with the naked eye, because that is determined by the surface composition of the planet. However, astronomers define a photometric color as the difference in magnitude of the object between neighboring wavelengths. If you were to observe a planet in the infrared, and make careful photometric measurements of its brightness at two wavelengths, you could estimate its black body temperature in that way. The 'redder' the planet is, the cooler it is.