def _create_var_metric_filename(input_dir, model_forcing, var, metric,
                                startdate):
    """Create path to S2S metric file."""
    name = f"{input_dir}/"
    name += f"{model_forcing}_"
    name += f"{var}_"
    name += f"{metric}_"
    name += f"init_monthly_{startdate.month:02d}_{startdate.year:04d}"
    name += ".nc"
    return name