Is the sun closer or farther in Winter?

Yes.

OK, that's not very helpful. The Earth's orbit is an ellipse, farthest away from the Sun on July 4, closest to the Sun on January 4. (Plus or minus one day due to the cycle of leap years!) So in the northern hemisphere, the Earth is closest to the Sun in the winter, and farthest from the Sun in the summer. In the southern hemisphere, the Earth is closer in the summer and farther away in the winter.

The difference isn't very much; only about a million miles or so.