def diff_month(date_series_1, date_series_2):
    """
    Computes Elementwise time difference between two series of datetime dates, in months.

    :param date_series_1:
    :param date_series_2:
    :return: Difference between times in months.
    """
    date_series_1_year, date_series_1_month = date_series_1.map(lambda x: x.year), date_series_1.map(lambda x: x.month)
    date_series_2_year, date_series_2_month = date_series_2.map(lambda x: x.year), date_series_2.map(lambda x: x.month)

    return abs((date_series_2_year - date_series_1_year) * 12 + date_series_2_month - date_series_1_month)