I was astonished nobody complain about this yet! [;)]
The color of the sun light computed at the two best qualities depends on the location of the sun in the sky, meaning it's yellowish in the morning, the evening or even at almost any hour of the day if you chose a high latitude during the winter. As you can't set in Sweet Home 3D whether the weather is shiny or cloudy (that should change the temperature of the color), the workaround is to choose an hour during a summer day for example, or a night hour and add your own lights (enlarge them to get softer shadows).