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

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

    Parameters
    ----------
    vals : float
        float or array of floats
        Speed in SI units (m/s)

    Returns
    -------
    output: float
        float or array of floats
        Speed in km/hr

    Examples
    --------
    >>> from wradlib.trafo import si_to_kmh
    >>> print(si_to_kmh(1.))
    3.6
    """
    return vals * 3600.0 / 1000.0
