Task: Question Answering
Input (English): Passage: The average temperatures in January, coldest month, are, Luang Prabang 20.5 °C (minimum 0.8 °C), Vientiane 20.3 °C (minimum 3.9 °C), and Pakse 23.9 °C (minimum 8.2 °C); the average temperatures for April, usually the hottest month, are, Luang Prabang 28.1 °C (maximum 44.8 °C), Vientiane 39.4 °C). Temperature does vary according to the altitude, there is an average drop of 1.7 °C for every 1000 feet (or 300 meters). Temperatures in the upland plateux and in the mountains are considered lower than on the plains around Vientiane. 
Question: How many degrees Celsius difference, is the average temperature in January in Luang Prabang compared to the average temperature in April, in Vientiane? 
Answer type: Number 
Output (English): 18.9.