Yes, the average global temperature of the Earth is approximately 15 C (59 F). Due to the natural greenhouse effect, where certain gases in the atmosphere trap heat and keep the planet warmer than it would be otherwise according to NASA scientists. Without this effect, the average temperature would be around -18°C (0°F). This due to the earth-atmosphere energy balance in the balance between incoming energy from the Sun and outgoing energy from the Earth.

Energy that is released from the Sun is emitted as shortwave light and ultraviolet energy. When reaching Earth, some is reflected back to space by clouds, some is absorbed by the atmosphere, and some is absorbed by Earth.

However, since the Earth is much cooler than the Sun, its radiating energy is much weaker (long wavelength) infrared energy. We can indirectly see this energy radiate into the atmosphere as heat, rising from a hot road, creating shimmers on hot sunny days. The earth-atmosphere energy balance is achieved as the energy received from the Sun balances the energy lost by the Earth back into space. In this way, the Earth maintains a stable average temperature and therefore a stable climate. Using 100 units of energy from the sun as a baseline the energy balance is as follows:

The absorption of infrared radiation trying to escape from the Earth back to space is particularly important to the global energy balance. Energy absorption by the atmosphere stores more energy near its surface than it would if there was no atmosphere. Greenhouse warming is enhanced during nights when the sky is overcast. Heat energy from the earth can be trapped by clouds leading to higher temperatures as compared to nights with clear skies. The air is not allowed to cool as much with overcast skies. Under partly cloudy skies, some heat is allowed to escape and some remains trapped. Clear skies allow for the most cooling to take place.

The average surface temperature of the moon, which has no atmosphere, is 0°F (-18°C). By contrast, the average surface temperature of the Earth is 59°F (15°C). This heating effect is called the greenhouse effect.