def kmh_to_si(vals):
    """Conversion from km/hr to SI wind speed units

    Note
    ----
    Code was migrated from https://github.com/nguy/PyRadarMet.

    Parameters
    ----------
    vals: float
        float or array of floats
        Wind speed in km/hr

    Returns
    -------
    output: float
        float or array of floats
        Wind speed in SI units (m/s)

    Examples
    --------
    >>> from wradlib.trafo import kmh_to_si
    >>> print(np.round(kmh_to_si(10.), 3))
    2.778

    """
    return vals * 1000. / 3600.