too bad i didn't put in cops and PAP uniform in my uniform thread. it's too common knowledge for chinese, and yet it seems so difficult to explain to you people.
cops' uniform changed from oliver green to black in about 2000. PAP is about under the command of dept of public security (police), or i might be wrong about that since i never liked them... so the used to wear similiar unifrom as the cops, only it's military style, the cap badge is the same.
this is a tiananmen square guard, pretty similiar to the red square guards. and i think they can't wear the winter cap, since it won't look nice. there are guards standing beside the flag too, they have this vent on the ground, that fans out warm air.
and no, actually beijing could be quite cold in the winter. beijing could get -20 as well.
offtopicly, my second year in canada, a friend from south europe asked me if i ever seen a thing called snow in china, which made me speechless, because my hometown is much colder than south ontario.....