There's a specific green that means get inside.

If you have lived anywhere with real storms you know it. Nothing alive is that green. It's the green of a bruise, or of the water at the bottom of a quarry, and it comes over the sky in the late afternoon in summer, and the light goes wrong, and the birds shut up, and every animal including you receives the same message at the same time. Get inside. Nobody taught you that. You knew it before you had words for the color.

I've been thinking about how many of these there are. Not weathers. Moods. Conditions of the sky that you recognize the way you recognize a person's face across a room, before you can say what you are recognizing.

The green one

The green one is the one I'm most afraid of and I have only seen it four or five times. It's a tornado sky, or a bad hail sky, and what makes it so strange is the stillness. The air stops. It gets heavy. The trees, which have been moving all day, go rigid, and the temperature drops several degrees in a minute, and the green pours in from one side like something being spilled.

Then it either happens or it does not. Most of the time it does not, and the green goes gray and then it just rains, hard, ordinary rain, and everybody comes out onto their porches feeling foolish and relieved. But you don't feel foolish for long. Because you know that the one time you ignore it'll be the time.

Fog

I live in fog now. I did not grow up with it and I did not expect to have feelings about it, and I have a lot.

Fog isn't a mood of the sky so much as the sky coming down to your level to see what you're doing. It arrives in the afternoon, over the hills, in a shape you can watch, a slow gray animal pouring over a ridge, and by evening it has swallowed the streetlights and the tops of the buildings and you're walking in a room with no ceiling. Sound changes. Everything is closer. A person coming toward you on the sidewalk appears at twenty feet, fully formed, out of nothing.

People who have lived here their whole lives complain about it. I understand. But I've started thinking of it as a privacy the city grants itself. For a few hours the whole place is under a blanket and nobody can see anybody's business, and the foghorns go, and it feels, in a way I can't fully defend, like being forgiven for something.

The wind with a name

Joan Didion wrote about the Santa Ana, the hot dry wind that comes down off the California desert into Los Angeles a few times a year, and she said that the whole city knew when it was coming, that people got strange, that the wind was in the divorce statistics and the emergency rooms. She wasn't being poetic. There are winds like this in a dozen places, the foehn in the Alps, the mistral in Provence, the chinook, and every one of them has a name because every one of them has a personality. The locals talk about them the way you talk about a relative who's coming to stay.

I've been in one. Not the Santa Ana, another one, and I can report that she was right. The air was wrong. Everyone was irritable and nobody could say why. Doors banged. A friend and I had an argument about nothing that neither of us could afterward reconstruct. The wind was in the room, and it had a mood, and the mood wasn't ours but we caught it anyway, like a yawn.

Petrichor

And then the gentle one. The smell of rain on dry ground, which has a name, petrichor, which I love and never use because nobody knows it.

The smell is real and has a chemistry, an oil that plants release into dry soil and that the rain kicks up, and a compound made by soil bacteria that the human nose can detect at concentrations that make no sense, a few parts per trillion, better than a shark smells blood. Somebody once suggested we evolved that sensitivity because rain meant water and water meant living. I do not know if that's true. But I know the feeling, standing at a window when the first drops hit hot pavement, and the smell comes up, and something in the oldest part of the body relaxes and says, oh, good.

That's a mood too. The relieved one. The one where the sky has been holding something for days and finally lets go.

The last thing we cannot control

I think the reason we talk about weather so much, the reason it's the universal small talk, the thing you say to a stranger in an elevator, is that it is the last big thing that happens to everyone and that nobody can do anything about. Everything else has been brought inside. Temperature has a thermostat, light has a switch, distance has a car. The weather is still out there, still enormous, still in charge, and for a few minutes a day it makes us all the same size.

Talking about it only looks like small talk. It's two people acknowledging that they're both standing under the same thing and that the thing doesn't care about either of them. It's intimacy disguised as filler. The stranger in the elevator says "some rain, huh," and what he means is: we're both small, and it's fine.

Meeting them

So I've met the sky's moods, and the list so far is: the green one that means get inside, the fog that means you're forgiven, the wind that means everybody is going to be difficult today, and the rain on dry ground that means you can stop holding your breath. There are more. There's a particular gold in October at four in the afternoon that means something is ending and it is all right. There's a white flat sky in February that means nothing at all, for weeks, and you have to survive it.

I can't forecast any of them. Nobody can, past a week or so, and I've been told that's a law. But I can recognize them when they arrive, the way you recognize a face, and that seems like the better skill anyway. I've stopped treating the sky as a system I need to predict. It's a set of people I've met, and they come by when they come by, and I know them when I see them at the door.