Weather has been confirmed as the sole remaining subject two strangers may discuss without risk, following a review of every other available topic.

The exchange conveys no information, since both parties are standing in the weather.

“He said it was close,” said commuter Elspeth Vaughan-Tighe. “I said it was. That was the whole thing. It was excellent.”

The Institute for Ambient Civility reports the function of the exchange is not informational but structural: it confirms that neither party is a threat, and that they may now stand near one another in silence.

“Nobody is describing the weather,” said Dr. Sunniva Blackthorn. “They are saying, in the only permitted vocabulary, that they have noticed each other and intend no harm.”

Institute figures indicate the average weather conversation lasts eleven seconds and follows a fixed structure: a claim, an agreement, an intensifier, and a closing sound that is not a word.

Attempts to extend the exchange beyond three turns are described as hazardous.

“At turn four, a person must either introduce a fact or introduce themselves,” Blackthorn said. “Both are catastrophic at a bus stop.”

Vaughan-Tighe and the stranger stood together for a further nine minutes, boarded the same bus, and sat apart, having concluded their business.