Every school possesses a red flag, and the Vice Principal controls it. If the flag is hanging outside the teachers room it means that the heaters can be used in the classrooms. If it's not hanging then all the kids will be cold all day.
So as you can imagine I look for the red flag when I arrive at the schools. And all the schools have different rules - some schools hang the flag if the temperature is less than 8, and other schools wait until it is less than 6 degrees (no prizes for guessing which schools I prefer). One of the English teachers and I amused ourself yesterday thinking of ways to distract the Vice Principal to steal the flag and hang it out. Of course, heaters in the teachers room can be used regardless!