def y_axis_properties(title_text):
    """

    Parameters
    ----------
    title_text: str
        text to use for title

    Returns
    -------
    y_axis_properties_dict: dictionary
        dictionary of y axis properties that can be applied to plot

    """

    # Create dictionary of y axis properties
    y_axis_properties_dict = dict(
        showgrid=True,
        gridcolor="rgb(255, 255, 255)",
        hoverformat="%H:%M",
        tickfont=dict(size=10),
        title=dict(text=title_text, font=dict(size=10)),
    )

    # Return y axis properties dictionary
    return y_axis_properties_dict