During the planning phase of trips to Japan, I monitor two data sources in tandem. The first is that ever-shifting results screen, responding in real time to seasonal demand, route changes, currency shifts, and consumer behaviour. It tracks the rise and fall of flight costs and availability—a volatile, networked system, self-adjusting yet entirely human-made. Its only near certainty is that the longer one hesitates to buy, the worse the deal becomes for whoever’s left holding the credit card.

The second data source, by contrast, is influenced only in microincrements by human activity spread across years, decades, even millennia. It remains largely indifferent to the compressed timescale of a trip, shifting and settling on its own terms. It is, of course, the weather, a determinant on the kind of walks, travel, and work I’m likely to undertake. Both the weather report and the flight screen have been on my mind this week, with my September arrival in Tokyo drawing near.

September is classically the first month of Japanese autumn. Early on, it still feels like summer. The air clings with humidity, and daytime temperatures often exceed 30°C, driven by typhoons and their trailing weather systems. Precipitation is likely, especially in the first half of the month, as autumnal rain bands sweep across the archipelago. Toward October, stable air masses suppress cloud formation and begin to take hold, bringing clearer skies, cooler air, and an easing of the heat. I’ve always found September a moving time to be in Japan.

Last year, however, Tokyo recorded its latest-ever 35-degree day: 35.1 °C on 18 September. It marked a new high in data going back to 1875, according to The Asahi Shimbun. Days above 30 °C persisted deep into the month, eroding the former expectation that September would act as a transitional period. We are witnessing the subtle extension of summer, evident in temperature, humidity, and practical consequences, even if cultural convention has yet to adjust.

Forecasts from the Japan Meteorological Agency suggest above-average temperatures across Asia, a pattern linked to unusually warm seas surrounding Japan and the persistent extension of the North Pacific High, the subtropical pressure system that defines Japan’s summer. While both factors stem from natural variability, their effects are increasingly magnified by climate change, raising the likelihood that Tokyo will once again experience prolonged summer conditions. The clarity and coolness promised by autumn look to be postponed, the usual corridor of seasonal transition narrowed, if not closed.

In Tokyo, the effects of a lengthening summer are intensified. The Urban Heat Island Effect means that concrete holds the heat, while glass and asphalt release it slowly. In effect, the city breathes warmth back onto itself. Greener wards offer moments of reprieve. Nerima’s 60-hectare Hikarigaoka Park and Setagaya’s 39-hectare Kinuta Park, for example, serve as lungs to the city. But such spaces are exceptions. In denser wards like Toshima, where green space amounts to just 0.77 hectares per 1,000 residents—far below Nerima or Setagaya’s 5 to 6 hectares—there is little room for water to settle. Street trees and shrubs alone can’t meaningfully counteract the thermal load.

The built environment’s density further compounds the heat. Tall buildings and narrow corridors restrict air circulation, while the alleyways and passages that make the city so compelling to explore become heat traps in summer, holding both warmth and humidity in place. On top of this, vehicles, trains, and industrial systems contribute additional heat to an already saturated atmosphere, further limiting the potential for nighttime cooling. The result is a city that feels locked in an endless summer.

Adaptive Response

Tokyo’s prolonged summer elicits a range of responses, the most immediate being air conditioning. Few city dwellers go without it; it keeps trains, offices, and department stores at tolerable levels. Yet the way it pushes daily life indoors for much of the day can feel dispiriting. Air conditioning is also part of the problem: contributing to the Urban Heat Island Effect as the city’s narrow corridors fill not with breezes, but the hum of extractor fans expelling the indoor’s heat back onto the street. Still, I’m not prepared to remain inside all day. A broader perspective on Tokyo's adaptation to the heat is necessary.

Let’s begin with urban design. In the lead-up to the Olympics, several measures were introduced—among them, sections of road resurfaced with heat-reflective ‘cool pavement’. Ward offices, meanwhile, turned to residents, encouraging the cultivation of ‘green curtains’, climbing plants trained across balconies and building façades. A few prominent commercial developments, such as Coredo in Nihonbashi and Shibuya Stream, have adopted vertical greening too, though in practice, the foliage often feels more symbolic than substantial.

In recent years, I’ve often paused at a seating area in Ginza, beneath the shadow of the S&B sign, where a fine mist is released during periods of high heat. Passing through it offers a brief but perceptible drop in skin temperature, a slight reprieve in the density of summer air. Elsewhere across the city, similar systems appear more informally: strung above benches or suspended along shopping arcades, temporary installations that speak to the season’s intensity.

Water is also used in efforts to mitigate the heat in spaces designed for children. jabu-jabu-ike splash parks and shallow wading pools are scattered across the 23 wards. They serve a playful purpose, but also offer environmental value. Their evaporative surfaces help cool the surrounding air and reflect light, softening hardscapes that would otherwise retain heat. In parallel, some commercial developments have incorporated water as a cooling element. The Shibuya Stream complex, for instance, features cascading pools and a partially restored stretch of the Shibuya River.

Still, these measures remain piecemeal—useful in the moment, but ultimately surface-level responses rather than structural changes in how the city breathes. The most effective intervention remains the simplest: large-scale replacement of asphalt with greenery. Yet progress is slow, and in some instances, the trend moves in the opposite direction. The ongoing redevelopment of Jingu Gaien, a historically significant park, home to centenarian ginkgo trees, proposes replacing a portion of its parkland with commercial towers.

For those with business out in the city, then, self-preservation becomes essential. I keep a folding higasa sunbrella in the side pocket of my backpack, a practical defence against radiant heat. Its distant predecessor, the bamboo-and-paper wagasa, once conveyed status and refinement, held aloft by samurai and merchants in the 17th century. Over time, the form shifted and was refined into lightweight, UV-resistant fabrics. In present-day Tokyo, the higasa is above all practical, though it still signals something in its black, silver, or patterned palettes. Its seasonal reappearance is as emblematic of summer as the first translucent wave of umbrellas when the rains begin. The longer they remain open, the clearer it becomes: summer is overstaying its bounds.

Once the body is shielded from the sun, the next concern is cooling it. From the paper uchiwa handed out at summer festivals and on city streets, to the folding sensu drawn discreetly from elegant purses, fans have long formed part of Japan’s seasonal toolkit. Their contemporary successor is the USB-charged plastic fan worn on a lanyard or gripped in hand during the commute. Lacking the grace of a sensu or the cultural cachet of a lacquered wagasa, they’ve nonetheless become ubiquitous. The trend is measurable: global sales of portable fans were valued at around USD $559 million in 2024 and are projected to reach nearly USD $979 million by 2032. Electronics giant Yodobashi Camera lists well over 500 entries in its portable fan category—evidence enough that endurance has entered the marketplace as both necessity and style.

At the final line of defence, traditional food lore continues to influence Japan’s summer eating habits. Drawing on the yin and yang framework introduced from China, seasonal ingredients were classified as either cooling or fortifying. Watermelon, cucumber, chilled aubergine, and tofu fell on the yin side to temper the body’s internal heat. By contrast, unagi was considered yang: oily, rich, and prescribed for stamina, believed to replenish what the sun depleted. Today, grilled eel remains a summer staple, even in fast food chains, though its effects are arguably more psychological than physiological. A ritualised lift, as much cultural as nutritional.

By September, the peak of watermelon season has passed, and the midsummer haul of unagi is depleted. Still, one can always reach for the frozen Calpis bottle, usually found on the bottom shelf of konbini freezers. The sweet, lactic drink, frozen overnight until its core becomes crystalline, is an enduring Shōwa-era tactic against the heat. Friends often recall grandparents freezing bottles at home, long before convenience stores adopted the ritual. Its credentials within the yin–yang food system are questionable, high sugar content and PET packaging breaking with tradition somewhat. The physiology is sound, though: a slushy ice drink absorbs more heat than liquid alone, and a cold bottle pressed to the forehead or neck lowers skin and superficial blood temperature, reducing the sensation of heat.

But if you don’t see yourself navigating crowded city streets with a sunbrella in one hand, a sticky Calpis bottle in the other, and a USB fan swinging from your neck—on the verge of overheating nonetheless—there is one more alternative: to exit the city.

Escape Routes

However much one values slow travel, time is often short. For the purposes of this guide, long-distance escapes are off the table. Tokyo’s surrounding prefectures—Saitama, Chiba, and Kanagawa—might seem promising, though they offer little in the way of relief. On heat maps, their colours blend into the same band as the capital’s, the basin effect trapping humidity and raising night-time lows. For a meaningful drop in temperature, you need to move one layer further out, toward Shizuoka, Yamanashi, or Tochigi, where altitude and topography create cooler microclimates. A one- to two-hour trip to these regions can deliver a noticeable shift in the air.

From Tokyo Station, the Tōkaidō Shinkansen reaches Atami in Shizuoka Prefecture in as little as 45 minutes. The Chūō Line’s limited express Kaiji and Azusa trains run west into Yamanashi, arriving in Katsunuma—Japan’s wine country—in about 1 hour 20 minutes. And to the north, the Tōhoku Shinkansen makes Utsunomiya reachable in roughly 50 minutes, with onward connections to Nikkō. These are three routes I’ve taken in previous summers, each forming part of a practical perimeter of escape.

Katsunuma, set in a mountain basin in Yamanashi Prefecture’s wine region, is fringed by vineyards and the lower slopes of Mount Fuji. The contrast with Tokyo is most apparent at night: while Katsunuma cools into the mid-teens, the capital often lingers near 20 °C, its heat island effect preventing any real release. Even at its hottest, the local temperature tends to peak in the high 30s—less severe than Tokyo’s occasional 40 °C extremes. September coincides with the Kōshū grape harvest, a peak time for domestic wine tourism, when local wineries see an influx of visitors and activity. Yet beyond the major producers, the dusty late-summer lanes between smaller vineyards often remain calm.

Atami, facing the Pacific in Shizuoka, is warmed by the sea but tempered by coastal breezes. Roadside palms and a seafront promenade give the town a Mediterranean cast; in the evenings, the air carries salt and the scent of grilled seafood from the waterfront. Once a favoured destination for corporate retreats during the bubble years of the 1980s, it now feels caught in time—its hot springs and hotels preserving a Shōwa-era atmosphere suited to nostalgic documentary photography. Compared to Tokyo, the sea air cools the evenings by a degree or two, softening the heat with water and wind.

Nikkō, higher still in Tochigi and nicknamed the “refrigerator of Kantō,” offers the most significant contrast. Nights drop into the mid-teens, often cool enough for a jacket, its mountain air laced with cedar and the sound of water in motion. Shrines and temples sit within shaded groves, while waterfalls mark the ascent toward Lake Chūzenji, reinforcing a coolness that Tokyo’s streets cannot offer. With its blend of nature and heritage, Nikkō draws large crowds and faces increasing pressure from tourism. Still, as in Katsunuma during the harvest, the roads linking lesser-known sites remain rural, walkable, and restorative.

We’ll need to wait until September to know whether, under 2025’s conditions, the temperature drop at these destinations still registers as perceptible relief. But a change of scene still counts. Even modest environmental shifts can alter felt experience, easing the weight of repetition. These places fall along a familiar arc of escapes from the capital—offering, if not cooler air, then the sentiment of a summer break; if not respite, then a reframing. A way to ride out summer’s extended coda, with the city shimmering in the rearview.

Until we meet back in Tokyo,

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