my cong was very keen on having the meeting no matter what. I remember one occasion when we had a power cut in the middle of winter. Due to the fact that there was no windows to the hall (!) they opened the fire exit doors and the speaker stood with his back to the doors that were letting in the freezing cold wind, he read the talk with the aid of a torch, and everyone sat there getting more and more blue.
Another time the air con packed up in the middle of summer, it was like a sauna in the hall! we had about 5 people faint due to the heat, but the meeting went on...!