How Hot Is the Sun?

The surface of the Sun, known as the photosphere, reaches a temperature of about 5,800 kelvin (K; 10,000 degrees °F). This intense heat is what gives the Sun its glow, providing the warmth necessary for life on Earth.

Deep within the Sun, the temperature in the core is 15 million kelvin (27 million °F). This is the powerhouse of the Sun, where nuclear fusion occurs, converting hydrogen into helium and releasing energy that makes its way to the surface as sunlight. It is this fusion process that keeps the Sun shining brightly.

Interestingly, the Sun’s atmosphere also has some unexpected temperature twists. Above the photosphere lies the chromosphere, where temperatures rise to about 8,000 kelvin (14,000 °F). The corona, the Sun’s outermost layer, reaches 1 million kelvins (1.8 million °F). This is quite the temperature jump from the surface, and scientists are still unraveling the mysteries of why the corona is so much hotter than the layers below it.