def speed_conv(val, centigrade):
    """
    Convert windspeed ``val`` to MPH or KPH, returning both the integer
    value and brief descriptor as tuple, fe. (10, u'MPH',). We re-use
    the session boolean 'centigrade' as weather or not to use MPH or KPH,
    (centigrade is metric, otherwise imperial). This isn't 100% accurate,
    but close enough for our needs ..
    """
    try:
        val = int(val)
    except ValueError:
        return '', ''
    if not centigrade:
        return val, u'MPH'
    else:
        return int(float(val) / 0.62137), 'KPH'
