get_season_for_date.php

<?

/**
 * Takes a date, returns the meteorological season of that date, by month. Not equinox/solstice.
 * Only works for the northern hemisphere.
 *
 * @link https://en.wikipedia.org/wiki/Season#Meteorological
 * @param string $date
 * @return string
 **/
function get_season_for_date(string $date)
{
  if (is_null($date)) {
    return false;
  }

  $date = new DateTime($date);
  $month = intval($date->format("m"));

  $season_ranges = [
    "spring" => [3, 4, 5],
    "summer" => [6, 7, 8],
    "autumn" => [9, 10, 11],
    "winter" => [12, 1, 2]
  ];

  $result = array_reduce(array_keys($season_ranges), function ($carry, $key) use ($season_ranges, $month) {
    $curr = $season_ranges[$key];

    $is_season = in_array($month, $curr);
    if ($is_season) {
      $carry = $key;
    }

    return $carry;
  });

  return $result;
}

echo get_season_for_date("june 21st");