<?php

function currentSeason($winter = null, $spring = null, $summer = null, $autumn = null)

{

    $month = (new DateTime)->format('n');

    if (in_array($month, [12, 1, 2])) {

        return $winter;

    } elseif (in_array($month, [3, 4, 5])) {

        return $spring;

    } elseif (in_array($month, [6, 7, 8])) {

        return $summer;

    } elseif (in_array($month, [9, 10, 11])) {

        return $autumn;

    }

}

echo currentSeason('зима', 'весна', 'лето', 'осень');