Is a blue supergiants hotter than a red supergiant?

Yes, blue supergiants are significantly hotter than red supergiants. Blue supergiants typically have surface temperatures ranging from about 10,000 to 50,000 Kelvin, while red supergiants usually have temperatures between 3,000 and 4,000 Kelvin. This difference in temperature is due to the varying stages of stellar evolution and the mass of the stars; blue supergiants are more massive and have burned through their hydrogen fuel more rapidly than their red counterparts.