time_filter_yield.php

<?php

/**
 * @param array $reports
 * @param string $start
 * @param string $end
 * @return array
 */
function timeFilter(array $reports, $start, $end)
{
    $start = strtotime($start);
    $end = strtotime($end);

    foreach ($reports as $report) {
        $current = strtotime($report['date']) ;
        if ($start <= $current && $current < $end) {
            yield $report;
        }
    }
}

$reports = [
    ['id' => 1, 'date' => '2015-01-01 00:00:00'],
    ['id' => 2, 'date' => '2015-01-02 00:00:00'],
    ['id' => 3, 'date' => '2015-01-03 00:00:00'],
    ['id' => 4, 'date' => '2015-01-04 00:00:00'],
    ['id' => 5, 'date' => '2015-01-05 00:00:00'],
];

var_export(iterator_to_array(timeFilter($reports, '2015-01-02', '2015-01-05')));

# => array (
#  0 =>
#  array (
#    'id' => 2,
#    'date' => '2015-01-02 00:00:00',
#  ),
#  1 =>
#  array (
#    'id' => 3,
#    'date' => '2015-01-03 00:00:00',
#  ),
#  2 =>
#  array (
#    'id' => 4,
#    'date' => '2015-01-04 00:00:00',
#  ),
# )