Natural air-conditioning

Despite today being declared a public holiday, I reported to work this afternoon to prepare lecture slides for the one course I'm teaching for the first time. With the relatively chilly weather--outdoor temperatures have been hovering in the lower 20s--we've been having these past few weeks I decided not to turn on my air-conditioning unit and just open the windows of my office. What a relief not to have the air-conditioning unit humming in the background and interfering with listening to my classical music.