The Earth is divided into two hemispheres; the northern hemisphere and the southern hemisphere. While the plane of incline is greater during the months between April and September in the northern hemisphere, the other six months in the southern hemisphere witness the same incline. Hence, summer in the northern hemisphere is winter in the southern hemisphere.
The effect of tilt of the Earth's axis determines day length, solar zenith at noon, and the length of associated seasons. However, the weather differences noticed between places in the same hemisphere are mainly due to the elliptical orbit of the planet, the path around the sun.
Meteorologically, the summer and winter solstice refers to the maximum and minimum proximity of the hemisphere to the sun. The tilt of the Earth, at any given point of time, on its imaginary axis is a major influence on seasonal temperature variations.
The properties of orbital eccentricity influence Earth temperature; however, it is commonly observed that the Earth is warmer when it is farthest along the elliptical orbit. This is mainly due to the presence of extensive land mass in the northern hemisphere. Land heats faster than open water bodies, and retains heat.