Question

I would like to know if there is some easy way to identify seasons: spring, summer, autumn or winter. I’m have to generate a ‘resume’ and I’d like that if a period of working roughly fits a season (not exactly but with a +/-10 days error for example) it returns spring, summer, autumn or winter.

Like:

• input: 25/06/2010, 30/09/2010
• output: Summer 2010

(In Spain summer is between 21 July and 20 September)

• input: 02/02/2009, 30/04/2010
• output: 2009-2010

Any idea how to do this?

Answer 1

As you are looking for a season for a period I quickly wrote this function, it can be improve and may have some bugs but you have somewhere to start.

function season($period) 
{
    $seasons    = array(
        'spring'    => array('March 21'     , 'June 20'),
        'summer'    => array('June 21'      , 'September 22'),
        'fall'      => array('September 23' , 'December 20'),
        'winter'    => array('December 21'  , 'March 20')
    );

    $seasonsYear = array();

    $start      = strtotime($period[0]);
    $end        = strtotime($period[1]);

    $seasonsYear[date('Y', $start)] = array();

    if (key(current($seasonsYear)) != date('Y', $end))
        $seasonsYear[date('Y', $end)] = array();

    foreach ($seasonsYear as $year => &$seasonYear)
        foreach ($seasons as $season => $period)
            $seasonYear[$season] = array(strtotime($period[0].' '.$year), strtotime($period[1].' '.($season != 'winter' ? $year : ($year+1))));

    foreach ($seasonsYear as $year => &$seasons) {
        foreach ($seasons as $season => &$period) {
            if ($start >= $period[0] && $end <= $period[1])
                return ucFirst($season).' '.$year;

            if ($start >= $period[0] && $start <= $period[1]) {
                if (date('Y', $end) != $year) 
                    $seasons = $seasonsYear[date('Y', $end)];   
                    $year = date('Y', $end);

                $nextSeason = key($seasons);
                $nextPeriod = current($seasons);                
                do {                    
                    $findNext   = ($end >= $nextPeriod[0] && $end <= $nextPeriod[1]);

                    $nextSeason = key($seasons);
                    $nextPeriod = current($seasons);
                } while ($findNext = False);

                $diffCurr   = $period[1]-$start;
                $diffNext   = $end-$nextPeriod[0];

                if ($diffCurr > $diffNext)
                    return ucFirst($season).' '.$year;
                else {
                    return ucFirst($nextSeason).' '.$year;
                }
            }
        }
    }
}

echo season(array('07/20/2010', '08/20/2010'));
echo "\n";
echo season(array('06/25/2010', '09/30/2010'));
echo "\n";
echo season(array('08/25/2010', '11/30/2010'));
echo "\n";
echo season(array('12/21/2010', '01/01/2011'));
echo "\n";
echo season(array('12/21/2010', '03/25/2011'));

Result:

/*
Summer 2010
Summer 2010
Fall 2010
Winter 2010
Winter 2011
*/

And the except you want for “season year overflow”:

if (date('Y', $end) != $year) 
    return $year.'-'.date('Y', $end);

Instead of:

if (date('Y', $end) != $year) 
    $seasons = $seasonsYear[date('Y', $end)];   
    $year = date('Y', $end);

Note: Winter is coming.