Give 'em a break. They feel the cold more than you.
At home I'm in a tshirt and shorts (hotpants obvs) while my housemate shivers under 3 layers of clothes and a blanket.
At work my desk mate is wrapped up like an Inuit while I'm sat semi-naked peeling my sweaty knackers off my thigh.
Live and let live though, eh?
Vive la difference!
Alternatively, it's not that fucking cold, take some iron tablets and man/woman the fuck up.