temperature

Official Hardware Classic Yún
1

I'm using Yun with LM35DZ to acquire the temperature. I note that every few seconds the value of temperature change (about of 1,5 °C). Why ?
What other sensor can I use ? I need 0,5 °C precision

2

http://playground.arduino.cc/Main/LM35HigherResolution#.UyNq1PldV8E