During the winter of the northern hemisphere, the Earth is closer to the Sun; this (all other things being equal) makes our winters a little milder than those of the southern hemisphere, and makes their summers hotter.
True if Earth was in a concentric orbit...but it’s NOT! It’s in an elliptic orbit, which all natural orbits are! Only controlled satellites are in man-made circular orbits. That globe thing called an orrery is the worst teaching tool ever! It’s shocking how many people don’t know that! I also was taught the planets are in circular orbits.