Just a quick thought, dont know if it's been mentioned before.....Clothes could maybe have an impact on the level of exposure you suffer when it is raining at night and so on.... Like a waterproof jacket might give you an extra hours worth of worry free running/surving outside, whereas a tshirt would instantly get wet and you would suffer exposure faster. likewise if it's a warm day you wouldn't be running around in something thats too hot, maybe you'd suffer from heat stroke or something....