"The tungsten atoms and the filament become extremely hot, typically about 2500 °Celsius."

2800 K

"Tungsten." A History of Technology. Oxford, 1958: 98-99.

"The development of tungsten, melting at 3410 °C, as a lamp filament began about 1904, and this metal has been used almost exclusively since 1911."

<3700 K

"Incandescent Lamp." Encarta. Microsoft, 1998.

"When electric current flows through the filament, it heats the filament to a temperature of about 3000 °C (about 5000 °F), causing the filament to glow and provide light."

3300 K

Incandescent lamps are the most common sources of electric lighting. The most
common incandescent lamp is the conventional household bulb. Incandescent lamps
are based on the principle of incandescence, which states that solids and gases
emit visible light when heated to a high enough temperature. The bulb consists
of a filament positioned inside a glass bulb filled surrounded by an inert gas.
This gas is usually composed of a combination of argon and nitrogen, which does
not react with the tungsten or the bulb. The gas also acts to extend the life
of the filament. The filament is a piece of thin coiled wire and is part of the
light bulb that produces the light and is usually made out of tungsten -- a material
that can withstand incredibly high temperatures without melting. Despite its miniscule
appearance, the filament is about one meter in length wound into a spiral which
is then wound again into wider spiral. This spiral design increases the efficiency
of the bulb. Electric current flows through the filament when the lamp is turned
on. The electrons, which make up the electric current carry energy and collide
with the tungsten atoms which then gain kinetic energy. This increases the temperature
of the filament to about 2500 °C. As a result the filament glows.