def process_hour_group(df):
    """
    Prepare data to make hourly plots
    :param DataFrame df: Pandas DataFrame for the data to process
    :return: Processed Pandas DataFrame
    """
    df_hour = df.copy()
    df_hour['hour'] = df.index.hour
    df_hour['isweekday'] = df.index.dayofweek < 5
    return df_hour