<?php
$data = 'blah blah
var obTemperature = "55";
var obIconCode = "01";
more blah';
preg_match('/var obTemperature = "(\d+)";/', $data, $match); $temperature = $match[1];
echo $temperature;
PD9waHAKCiRkYXRhID0gJ2JsYWggYmxhaAp2YXIgb2JUZW1wZXJhdHVyZSA9ICI1NSI7CnZhciBvYkljb25Db2RlID0gIjAxIjsKbW9yZSBibGFoJzsKCnByZWdfbWF0Y2goJy92YXIgb2JUZW1wZXJhdHVyZSA9ICIoXGQrKSI7LycsICRkYXRhLCAkbWF0Y2gpOwokdGVtcGVyYXR1cmUgPSAkbWF0Y2hbMV07CgplY2hvICR0ZW1wZXJhdHVyZTs=