Temporary impairments are there only for a moment in time. Someone can have trouble with their eyesight, due to a temporary condition such as hay fever. Or someone may have broken their arm which prohibits them from using this arm for typing on a computer. Temporary impairments can be physical, but cognitive as well. And they occur a lot more than you think; sun glaring at your screen outside may limit your view of the screen, a bad internet connection on the train causes your website to load slow or a noisy environment can make you focus less on audio.