Often times, the rising or setting sun will show up on National Weather Service radar screens as a spike in the direction of the sun. Below you will see a series of images from the 1st of every month (in UTC time) since December 1, 2005 of the sunset spike as seen from the Louisville NWS radar. You can clearly see that the direction that the sun sets varies during the year, in the northwest during the summer and in the southwest in the winter.
Click here for a cool loop of the imagery (filesize 713kb). Let the loop fully download for the best effect.