According to the 1996 US Ephemeris, on the 21st of each month, the distance to the Sun is:
Month...............distance January 0.9840 February 0.9888 March 0.9962 April 1.0050 May 1.0122 June 1.0163 July 1.0161 August 1.0116 September 1.0039 October 0.9954 November 0.9878 December 0.9837 .................................
where 1.0 is the Astronomical Unit whose distance is 149,597,900 kilometers As you can see, the Earth is farthest from the Sun when the Northern Hemisphere is in the summer season, and closest in the winter. If you were living in the Southern Hemisphere, the seasons are reversed so that in the summer, the Sun is closest and in the winter it is farthest.