Six Weeks of Grey

Every morning in June I tip a litre of water out of a plastic tank and pour it down the kitchen sink. The tank belongs to the dehumidifier in the corner of the front room, and it fills overnight, every night, for about six weeks. That's tsuyu. Not a storm, not a typhoon, nothing you'd photograph. Just the air slowly turning to water and the quiet, daily business of getting it back out again.

This is the season nobody puts on a poster. Spring has the cherry blossom. Summer has the festivals and the heat you can describe to people back home. Tsuyu has grey. Six weeks of low cloud sitting on the country like a wet towel, somewhere between the last of the cool and the start of the real swelter. Locals endure it. After a few years here, so do I.

The Front Moves North

The grey isn't random. It arrives on a schedule, more or less, and it moves.

Tsuyu is a front: a long stationary boundary called the baiu zensen, where warm wet Pacific air pushes up against cooler air from the continent and neither side wins. The two stall over the archipelago and the rain settles in. It's the same mechanism that makes the cherry blossom front sweep north each spring, only this one brings drizzle instead of petals, and it lasts a lot longer.

It starts in the south. Okinawa goes first, usually around the second week of May, a full month ahead of everyone else. Then the front climbs Kyushu, Shikoku, up through Kansai and Kanto, reaching the Tohoku region in the north by mid-June.^[1] Where I live in Hyogo, onset normally lands in the first week of June and the rain hangs around until somewhere near the third week of July.

The Meteorological Agency announces the start — tsuyu iri — region by region, the way it announces the blossom. The declarations are provisional, revised later once the data settles, which tells you something about how slippery the whole thing is to pin down. The front doesn't cross a line on a map. It sloshes.

None of this means daily rain. That's the part people get wrong before they live through one. Tokyo's wettest tsuyu days run to maybe a forty-five per cent chance of rain.^[2] So plenty of mornings are merely overcast, with the rain holding off until you've left your umbrella at home. The defining weather isn't the downpour. It's the grey that never commits.

The War Against Damp

Indoors, the humidity climbs and parks itself there.^[3] You feel it before you read it on anything. Towels never quite dry. The tatami goes slightly tacky. Salt clumps in the shaker. And the laundry stops working.

Hanging washing outside is pointless when the air is already saturated, so it comes indoors — heyaboshi, the indoor dry. Everyone does it. Racks go up in the front room, the spare room, across the bath. The problem is that clothes dried slowly in still, damp air develop a smell: flat, faintly sour, the unmistakable scent of fabric that took two days to dry when it should have taken three hours. There's a word for it on the detergent bottles, because of course there is: there's an antibacterial heyaboshi detergent at the drugstore, a whole shelf of it.

So you fight back. The dehumidifier runs all day, which is where my morning litre comes from. An air circulator gets pointed straight at the rack to keep the air moving. The air conditioner has a dry mode that pulls moisture without dropping the temperature much. The flats lucky enough to have a bathroom dryer, or a gas dryer like Rinnai's Kanta-kun, which does a full load in about fifty minutes,^[4] skip the whole problem. Mine isn't one of them. And does any of it work? Sort of. You don't beat the damp during tsuyu. You hold the line.

Then there's the mould. Condensation beads on single-glazed windows overnight and runs down into the frames, and if you don't wipe it, black spots bloom in the rubber seals. Kabi turns up in the grout, behind the wardrobe, on the back of the genkan cupboard, on a leather belt you forgot about. The countermeasure is a bottle of bleach spray with a name that translates, roughly, to Mould Killer, and a bathroom extractor fan you're supposed to leave running around the clock.

The Umbrella Lifecycle

The clear plastic umbrella is one of the great unsung Japanese inventions. White Rose came up with the vinyl version in the postwar years, and the design has barely changed since: transparent dome, you can see where you're going, costs about ¥500 in the barrel by the door of every convenience store.^[5]

During tsuyu, that barrel is the centre of a small economy. You leave home under clear skies, it pours by lunchtime, so you buy one at the konbini near the office. Rain stops by evening, you forget the umbrella on the train. Next morning it's raining again, so you buy another. Why does everyone own the same umbrella, repeatedly? Because the barrel by the konbini door makes it the path of least resistance. The racks outside stations fill with identical clear domes, and nobody can ever find theirs.

The umbrella vending machines that appear at station exits run on the same logic. Officially these things aren't disposable, and the people who make them would rather you stopped treating them that way. But six weeks of buy-lose-rebuy makes a strong case for the opposite. Mine never last. One season, four umbrellas.

Inside every department store entrance you'll find the rituals that grew up around all this. The plastic sleeve dispenser, so your dripping umbrella doesn't soak the floor. The locked umbrella stands. The damp-sleeve smell of a hundred wet commuters in a train carriage, windows fogged on the inside, everyone reading their phones and pretending not to drip on each other.

Hokkaido Sits It Out

There's one part of the country the front never reaches. Hokkaido has no official tsuyu. The baiu zensen weakens as it moves north and falls apart before it gets that far, so the Meteorological Agency simply leaves Hokkaido off the rainy-season table entirely.^[1]

It's not quite bone dry up there. Some Junes bring a cool, damp spell of their own, driven by sea air off the Okhotsk rather than the main front, and locals have a name for it. But it's lighter than the real thing, and it isn't officially declared. For six weeks of the year, Hokkaido is the part of Japan you flee to. Plenty of people from Honshu do exactly that.

The One Good Thing

For all the grumbling, tsuyu earns one entry in the seasonal calendar that does end up on posters. The hydrangeas. Ajisai come into their own in June, and they like the wet, which is rather the point. The temples plant them on purpose, and the season belongs to them.

That's the trade. You take the grey, and somewhere in it there's a wall of blue flowers glowing under cloud, looking faintly smug about the weather everyone else is complaining about.

And then, around the third week of July in this part of the country, it lifts. Tsuyu ake, the agency calls it, the end of the rains. The grey burns off, the cicadas start, the dehumidifier finally gets a rest. What replaces it is its own kind of ordeal — the heat that actually does deserve a warning — but that's a different season. For now there's just the tank to empty, the rack to rotate, and another forty minutes to Koshien if the evening clears enough for a game.