About ${\displaystyle 1360W/m^2}$ from the Sun reaches Earth—specifically, the top of Earth’s atmosphere directly facing the Sun.

But since Earth is a rotating sphere, half its surface is facing away from the Sun at any given time. Other factors, such as latitude and time of year, also affect how much solar energy is received by different places.

When averaged over the entire Earth and year, only ${\displaystyle 340W/m^2}$ from the Sun reaches the top of Earth’s atmosphere.