My cintiq is usually fine and we normally get over 30C in summertime (35-40 is a bit more common). I'm reasonably certain their operational temperature goes to at least 40 but it's been a while since I checked and maybe I'm remembering wrong. Could probably find out online anyway. But you seem to also have snow there so perhaps it's different with a bigger temperature range? Over here it rarely drops too far below 10 in winter. I'll normally crank the aircon if it's going to be close to or over 35C just to make sure the electronics will be okay.