do you mean P/T = constant (for an ideal gas) For air humidity will factor in, but then if you cool air down, the humidity falls (as the water condenses out). There are tables for "standard" atmosphere.
But if you're looking inside a vacuum tube, then what does the question mean ? (how does the "pressure" of a vacuum change with temperature ?)
"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.