* Temperature and Color: The color of a star is directly related to its temperature. Red stars are cooler than yellow or blue stars.

* Red Giant Stage: Red giants are stars in a later stage of their life. They have expanded significantly and have a cooler surface temperature than they did in their main sequence stage. However, they are still much hotter than many other types of stars.

* The Coolest Stars: The coolest stars are called red dwarfs. These are much smaller and less massive than red giants, and they have surface temperatures of around 2,000 to 3,500 degrees Celsius (3,632 to 6,332 degrees Fahrenheit).

In summary: Red giants are relatively cool compared to their main sequence stage, but they are still much hotter than red dwarfs, which are the coolest stars.