Factor's that influence the Earth's weather

There are a few different things that influence the Earth's weather. They are: thermal energy, uneven distribution of thermal energy, and water vapor in the atmosphere.

Thermal energy comes from the sun in the form of light. Scientists refer to it as insolation. Insolation stands for "incoming solar radiation". The Earth is placed perfectly in space to absorb just the right amount of insolation from the sun.

Aphelion is the point of which the Earth is farthest from the sun while perihelion is just the opposite. Perihelion is the point at which the Earth is closest to the sun.

The hemisphere is split into two regions. They are: The Northern Hemisphere, which contains the regions north of the equator and the Southern Hemisphere  which contains the regions south of the equator. The USA is in the Northern Hemisphere... obviously.

Uneven Distribution of Thermal Energy
The Earth's axial tilt allows the sunlight to shine on different parts of the Earth. The Earth's light shines most directly on the equator. This is why there is a warmer climate near the equator. Above and below the equator, the sun's light shines on the Earth at an angle, making it's temperatures vary.