The primary reason some parts of the Earth experience warmer days than others is the angle at which the sun strikes Earth. This angle affects the intensity of sunlight that reaches a specific area; when the sun’s rays hit the surface at a steeper angle, the energy is more concentrated, leading to warmer temperatures. In contrast, areas that receive sunlight at a shallower angle tend to be cooler.
This variation in temperature is also influenced by other factors such as the Earth's tilt, distance from the sun, and geographical features, but the angle of sunlight is the key factor in determining temperature differences.