reportAggregateDF['PORT_WEIGHT'].ix[idx] = reportAggregateDF['SEC_WEIGHT_RATE'
    ][(reportAggregateDF['PORT_ID'] == portID) & (reportAggregateDF[
    'SEC_ID'] == 0) & (reportAggregateDF['GROUP_LIST'] == ' ') & (
    reportAggregateDF['START_DATE'] == reportAggregateDF['START_DATE'].ix[
    idx]) & (reportAggregateDF['END_DATE'] == reportAggregateDF['END_DATE']
    .ix[idx])].sum()
Создавайте SUMIFS в стиле Excel в Pandas