Lightning can be up to 18,000 degrees Fahrenheit, which is almost two times the surface temperature of the sun! If lightning is so burning, why is it that we get our energy from the sun? Though lightning is scorching hot, its radiant energy pales in comparison with the sun’s. Whereas it’s true that lightning can set a tree on fire, the distance to its target must be very undersized for it to feel the full heat of lightning. The sun’s core though is close to 15 million degrees Fahrenheit!