Japan loosens office dress code as heat and energy fears rise

Japan has begun this year’s summer season with record-breaking heat and mounting concern over energy security, placing fresh pressure on one of the country’s most rigid workplace traditions: office dress codes.

Tokyo is now encouraging civil servants and other staff under its administration to wear shorts, T-shirts and trainers to work as part of efforts to reduce air-conditioning use and save energy.

The move marks a striking shift in Japan’s formal office culture and builds on the long-running Cool Biz campaign, which was designed to help the country cut electricity consumption.

The policy is not being driven by fashion, but by a combination of extreme weather and global geopolitical tensions that have heightened fears over energy supply.

Japan records first extremely hot day of the year

Japan’s latest weather warning came into sharp focus on Monday (May 18), when the country officially recorded its first “extremely hot day” of the year after temperatures in several regions climbed above 35 degrees Celsius.

The unusually early heat was caused by a strong high-pressure system that cleared the skies and brought mid-summer conditions more commonly seen in July. The intense heat has been described in Japan as “kokusho”, meaning brutally hot weather.

In Hita city, Oita prefecture, the temperature reached 35.3 degrees Celsius at 12.55pm, setting a new local record for the earliest extremely hot day of the year. The previous record had been set on May 24, 2013.

Local authorities have warned residents to take precautions against heatstroke, especially as many people’s bodies may not yet have adjusted to the sudden rise in temperature. People have been advised to use air conditioning when necessary, drink water regularly and replenish salt and minerals to protect their health.

Energy security fears add pressure

Another factor behind Tokyo’s push for more relaxed workplace clothing is concern over energy security linked to global geopolitical tensions, including the war involving the United States, Israel and Iran, which has pushed up global energy prices and raised concern over shortages of petroleum products, including jet fuel.

Japan, which has limited natural resources and depends heavily on imported energy, remains vulnerable to disruptions in global supply. The country relies on the Middle East for around 90% of its crude oil, with key shipping routes passing through the Strait of Hormuz.

Experts have warned that if shipping through the route does not return to normal soon, Japan could face a serious crude oil shortage, potentially forcing businesses and households to cut electricity and fuel consumption more strictly, echoing the oil shocks of the 1970s.

Local media reports said Japan was preparing to release an additional 20 days’ worth of oil reserves from May 1, while also seeking alternative suppliers whose shipments do not need to pass through the Strait of Hormuz.

From Cool Biz to shorts in the office

Under pressure from both energy concerns and extreme weather, Tokyo Governor Yuriko Koike has moved to expand the spirit of Cool Biz, the energy-saving campaign she helped launch two decades ago while serving as environment minister.

The new guidance encourages staff to wear clothing that is comfortable and breathable, including polo shirts, T-shirts, trainers and, most notably, shorts, depending on the nature of their work.

Cool Biz, launched in 2005, originally encouraged workers to remove neckties and suit jackets during the warmer months. However, it stopped short of allowing shorts in the workplace.

The latest move therefore represents a much bolder break from tradition, especially in a country where formal dress remains deeply embedded in office culture.

A Tokyo civil servant who wore shorts to work for the first time told the Yomiuri Shimbun that he had initially felt nervous, but later found them comfortable and said they helped improve his efficiency. He added that if temperatures rose further, he would consider starting work earlier and working from home on some days.

Asia adapts to harsher heat

Japan’s move reflects a wider shift across Asia, where countries are being forced to rethink working patterns as extreme heat becomes more common.

According to the Japan Meteorological Agency, last year was Japan’s hottest summer since records began in 1898. Temperatures of 40 degrees Celsius or higher are no longer considered exceptional, prompting meteorological authorities to use stronger terminology such as “kokusho” to describe the severity of the heat.

South Korea has also faced severe heat, with authorities imposing restrictions and rationing energy use while encouraging people in Seoul to walk or cycle for short trips instead of driving. Around 20% of South Korea’s natural gas also passes through the Strait of Hormuz.

Vietnam has introduced energy-saving measures and urged businesses to allow employees to work from home to reduce commuting and transport demand. The Philippines and Sri Lanka, meanwhile, have promoted four-day working weeks as part of broader energy conservation efforts.

How short is too short?

Although wearing shorts to work may offer a practical response to heat and energy-saving needs, the policy has also revived debate over workplace culture and professional dress.

Shorts have long been regarded as taboo in many offices because they are seen as too informal. A 2023 survey by Ipsos and The Wall Street Journal found that 41% of American workers considered it highly inappropriate for men to wear shorts in the office, regardless of how hot the weather was.

Attitudes, however, are changing in the post-pandemic workplace, especially among Gen Z and millennial workers. Hazel Clark, professor of design and fashion studies at Parsons School of Design, told Fortune that younger generations were helping push business culture towards more relaxed and flexible workwear.

Some etiquette and workplace image experts remain cautious. Myka Meier, founder of Beaumont Etiquette, warned that shorts could create problems unless organisations set clear standards, particularly because their length and style can vary widely.

Lisa Z Morgan, chair of fashion design at Pratt Institute, offered a more positive view, saying shorts can be styled in a polished and work-appropriate way if the design and length are chosen carefully. Still, she advised employees to use their judgement and consider the culture of each workplace.

Tokyo’s shorts policy shows how climate pressure and energy insecurity are reshaping not only how people work, but also what they wear. In an era of intensifying heat, even long-standing office traditions are being forced to adapt.