What is the average temperature of the sun?

The surface temperature of the sun is about 5780 K, which is 5500 °C or about 9900 °F. At the core it is much hotter: 15 million °C or 27 million °F. This is where nuclear fusion occurs.

The temperature varies on different parts of the Sun. For rexample, the visible part (photosphere) has a temperature of almost 6000 degrees Celsius, while the nucleus is estimated to be 15 or 16 million degrees.