It’s what people who don’t know each other talk about on elevators. And not about the weather at all. Chatting about the weather with strangers is about emotional comfort.

When someone says “Beautiful day today, isn’t it,” as you settle into that narrow elevator space, or at the bus stop, or waiting in line at the supermarket, the conversation is about feelings. The person speaking is looking to feel more comfortable with you and offering you a chance to feel more comfortable with him or her.

Being in close proximity with strangers  creates interpersonal tension. We can’t help it. Tension automatically seeks resolution. What do you do? Do you acknowledge the person now only a short distance away, or pretend not to notice? Avoidance is one strategy: never make eye contact and act as if nobody is there, even while your feelings tell you otherwise. In a supermarket checkout line you might leaf through a magazine. On elevators, we routinely avoid others by looking up at the floor numbers.

The other option is to break the tension by acknowledging the other person. It starts with eye contact. Then we have a choice: smile, nod, make a comment or strike up a conversation. If we choose to talk, the most non-controversial subject to talk about is the weather. Why risk offending, confusing, or generating even more tension by talking about anything else?

A comment about the weather evokes agreement and feelings of sympathy. “What a nice day!” shares a tiny sliver of happiness. “I wonder if this rain will ever end,” shares compassion about a mutual source of malaise. Both ends of the mini-conversation feel a tiny bit more connected for experiencing this emotion of liking or disliking the weather at the same moment.

This is how the human emotional system works. It motivates us to move from feelings of upset or discomfort to more harmonious feelings. It is always operating, managing our emotions in an effort to keep us stable and balanced, which is the strongest position from which to face whatever comes next.

In the Boston area, where I’m from, people who meet talk about the Red Sox. They assume that everyone around here is a Sox fan, and they’re usually right. The weather is an even safer topic. Wherever you go, when you want to break interpersonal tension at low risk, stick to the weather. When you do, recognize that you’re not focused on the skies at all. You are focused on having a slightly warmer relationship with the person in front of you.