Breaking the table by month Thymealeaf

Question

Good afternoon. Prompt as means of Thymealeaf to break the table on months. Now everything is displayed correctly sorted by date. But I need the beginning of each month to be signed with a string.

January.

January data

February

February data. Etc..

Table code

            <table  class="table table-bordered table-hover table-sm table-fit">
            <thead>
            <tr>
                <th>Дата начала по плану</th>
                <th>Должность и подразделение</th>
                <th>Шт.ед.</th>
                <th>Причина</th>
                <th>Дата окончания</th>
                <th>Включение в план</th>
                <th>Статус факт</th>
                <th>Дата смещения плана</th>
                <th>Филиалы</th>
            </tr>
            </thead>
            <tbody>
            <div th:each="d : ${descrirtion}">
                <tr class="table-light">
                    <td th:text="${#dates.format(d.start_date, 'dd.MM.yyyy')}"> </td>
                    <td th:text="${d.position} + ' ' + ${d.subdivision}"></td>
                    <td th:text="${d.staff_unit}"></td>
                    <td th:text="${d.reason}"></td>
                    <td th:text="${#dates.format(d.end_date, 'dd.MM.yyyy')}"> </td>
                    <td th:text="${d.status_onit} ? 'Подтверждено':'Не подтверждено'"></td>
                    <td th:text="${d.status_fact} ? 'Подтверждено':'Не подтверждено'"></td>
                    <td th:text="${#dates.format(d.new_start_date, 'dd.MM.yyyy')}"></td>
                    <td th:text="${d.name}"></td>
                </tr>
            </div>
            </tbody>
        </table>