Everyone’s talking about the weather but nobody’s doing anything about it.
It's one of the oldest traditions around. People have been using it as an excuse to strike up conversation for ages. Everyone can relate to the weather, all they have to do is look up at the sky and they can get in on the conversation.
When radio came out, people could begin to talk about programs that they listened to, because everyone with a radio could listen to the same things. Same goes for television. You probably know someone who watches the same shows as you on TV, and you talk about your favorite parts with them the next day. Well, radio and television were preceeded by the weather. It's a topic that anyone can comment on; everyone pays attention to the weather.
Even if it is considered by many to be a waste of time, talking about the weather is a sureshot way to begin conversation with persons of any education level. Although, your time may be better spent talking about the news, sports, politics or the new flavor at McDonalds. These are also topics that everyone is sure to know about.