json_decode()

連想配列にします。

<?php

$url = "http://weather.livedoor.com/forecast/webservice/json/v1?city=130010";
$json = file_get_contents($url);
$json = mb_convert_encoding($json, 'UTF8', 'ASCII,JIS,UTF-8,EUC-JP,SJIS-WIN');
$arr = json_decode($json,true);

echo('<pre>');
print_r($arr);
echo('</pre>');
?>

では、東京の今日の天気を表示させてみましょう。

<?php

$url = "http://weather.livedoor.com/forecast/webservice/json/v1?city=130010";
$json = file_get_contents($url);
$json = mb_convert_encoding($json, 'UTF8', 'ASCII,JIS,UTF-8,EUC-JP,SJIS-WIN');
$arr = json_decode($json,true);

$time = strtotime($arr&#91;description&#93;&#91;publicTime&#93;);

echo "<b>東京：今日の天気</b><br>";
echo $arr[forecasts][0][telop]."<br>";
echo $arr[description]."<br>";
echo date("Y/m/d H:i:s", $time)."<br>";

?>