I just watched 12 Angry Men (1957) again for the third or fourth time. About halfway through the movie the fan is turned on and it starts pouring rain outside the open windows. The fan and the rain create quite a bit of distracting noise for the second half or third of the movie. I racked my brain trying to understanding the significance of that from the filmmaker's perspective. Something so blatantly attention-getting as that much noise, very noticeable and obviously deliberate in the movie, must have a purpose. Increased tension? Some kind of metaphor? A psychological ploy?
So, what is the purpose of the noisy fan and rain through so much of the movie?