LaCrosse WS2300 station temperature difference

Hello,

I have a LaCrosse WS2300 weather station. The thermometer sensor is located in a shaded area. I also have an Oregon Scientific thermometer sensor in the same place.

However, when I compare readings, there seems to be a difference between them

You may look at this thread
http://www.weather-watch.com/smf/index.php?topic=3298.0
Also what is the specified accuracy for the two sensors?