On December 28, 2015, the temperature in a city was -4°C to 8°C. What is the temperature difference in the city on this day?
2015年12月28日，某市的气温为-4℃～8℃，这一天该市的温差是多少．
<gadget id="calculator">8 - (-4)</gadget>
<output>12</output>

<result>12</result>