# readTemperatures: string -> list-of-numbers
def readTemperatures(filename):
    """takes a file name that contains temperature data, and return the list of al the average temperatures"""
    inputFileRef = open(filename, 'r')
    finalList = []
    for aLine in inputFileRef:
        splitData = aLine.split()
        finalList.append(float(splitData[3]))
    return finalList