how hot is the sun?

The temperature of the Sun varies significantly depending on the layer or region being considered.

Core

The hottest part of the Sun is its core, where nuclear fusion reactions occur. Here, the temperature reaches approximately 27 million degrees Fahrenheit (15 million degrees Celsius) or about 10 million Kelvin245.

Radiative and Convection Zones

Beyond the core, there are the radiative and convection zones. The radiative zone, which surrounds the core, has temperatures ranging from about 7 million degrees Celsius at its innermost point to around 2 million degrees Celsius at its outermost point. The convection zone, which extends outward from the radiative zone, has temperatures that drop from about 2 million degrees Celsius to around 5,800 degrees Celsius as it approaches the surface4.

Photosphere (Surface)

The surface of the Sun, known as the photosphere, is relatively cooler with temperatures of about 10,000 degrees Fahrenheit (5,500 degrees Celsius). This is the layer that we can see from Earth and is the source of visible light245.

Sunspots

Sunspots, which are cooler regions on the photosphere, have temperatures ranging from about 5,400 to 8,100 degrees Fahrenheit (3,000 to 4,500 degrees Celsius)2.

Atmosphere (Chromosphere and Corona)

Above the photosphere lies the chromosphere, where temperatures range from about 11,000 degrees Fahrenheit (6,000 degrees Celsius) near the photosphere to around 7,200 degrees Fahrenheit (4,000 degrees Celsius) higher up.

The outermost layer of the Sun's atmosphere is the corona, which is surprisingly hotter than the surface. Temperatures in the corona can reach up to 1.8 million to 3.6 million degrees Fahrenheit (1 to 2 million degrees Celsius), a phenomenon that scientists have not yet fully explained235.

In summary, the temperature of the Sun varies dramatically from its core to its outer atmosphere, with the core being the hottest and the corona presenting an intriguing anomaly of being hotter than the surface.