HyperPhysics from Georgia State University here
- The center of the Sun: about 15 million degrees Kelvin (often stated as “Kelvins”).
- Radiative Zone: Temperature falls from about 7 million to about 2 million K across this zone.
- Convection Zone: drops from 2 million K to 5800K in this zone.
- Photosphere: about 5800K, although sunspots are about 3800K – that’s why they are dark.
- Chromosphere: 4300 to 8300 K from inside edge to outside edge
- Corona: about 1 million degrees