Because the earth’s orbit around the sun is elliptical

Because the orbit is elliptical, the distance between the Earth and the Sun is always changing.  Sometimes we're nearer to the Sun, and sometimes we're farther away from it.

NOW ... fasten your seat belt for the next factoid.  It's going to be
a boompy rade, and it may even shock you:

We are CLOSEST to the sun during the first few days of January ...
the middle of WInter in the northern Hemisphere.
and
We are FARTHEST from the sun during the first few days of July ...
the middle of Summer in the northern Hemisphere.