Static air temperature.

    Args:
        msg (String): 28 bytes hexadecimal message string

    Returns:
        float: tmeperature in Celsius degree

def temp45(msg):
    """Static air temperature.

    Args:
        msg (String): 28 bytes hexadecimal message string

    Returns:
        float: tmeperature in Celsius degree

    """
    d = hex2bin(data(msg))

    sign = int(d[16])
    value = bin2int(d[17:26])

    if sign:
        value = value - 512

    temp = value * 0.25   # celsius
    temp = round(temp, 1)

    return temp