In general, the temperature of a star relates to its color. At the top of the chart, along with the temperatures, are the Spectral Classes. The hottest stars are blue-white (class O), those in the middle temperatures are yellow (class G) and the coolest ones are red (class M). (Of course, when we say "coolest" about stars, we must realize that the lowest temperature for a star is almost 5000 degrees Fahrenheit.)