Tokyo Cool Biz hits 35°C and retailers rush casual workwear

For Japanese apparel retailers, Tokyo's heat emergency is not just a weather story—it is a demand signal. With Tokyo government workers now wearing shorts and sneakers under Cool Biz and temperatures running around 35°C at 72% humidity, Aeon, Fast Retailing and Aoki are racing to convert a cultural shift into sales of lightweight, quick-drying office wear. The question for retail operators is whether this season's dress-code relaxation becomes a durable consumer trend that lifts full-price mix and inventory turns.

The Tokyo Metropolitan Government's decision to encourage employees to abandon jackets and ties in favour of shorts, T-shirts and sneakers under the Tokyo Cool Biz campaign marks one of the most prominent institutional endorsements yet of casual office wear in Japan. The policy, reported on July 18, 2026, arrives as Tokyo temperatures climbed to around 35 deg C with average humidity of 72 per cent on July 14, and one day after the Japan Meteorological Agency and the Ministry of the Environment issued the capital's first heatstroke alerts of the summer. For a country long associated with dark suits and white shirts as the default office uniform, the programme signals both a practical response to intensifying heat and a cultural shift that has direct commercial consequences for retailers and apparel manufacturers.

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Japan's summer of 2025 was the hottest on record, with average nationwide temperatures running 2.36 deg C above the seasonal norm and more than 100,000 people hospitalised due to heatstroke.

The urgency of the moment is grounded in data. Japan's summer of 2025 was the hottest on record, with average nationwide temperatures running 2.36 deg C above the seasonal norm and more than 100,000 people hospitalised due to heatstroke. That record has made heat mitigation not just a comfort issue but a public-health and workplace-productivity imperative. Tokyo Cool Biz builds on a nationwide initiative first launched in 2005, but its explicit inclusion of shorts and sneakers for government staff represents a bolder standard than the earlier tie-optional guidance. Toru Suda, a 34-year-old Tokyo government worker, described the initial awkwardness of wearing a light blue polo shirt and knee-length navy shorts before the norm spread among colleagues. His experience illustrates how policy can normalise behaviour when enough workers adopt it.

For retailers and apparel manufacturers, the Cool Biz expansion is a demand catalyst. The source article notes that retailers such as Aeon have responded by expanding business-casual lines, while apparel makers including Fast Retailing and Aoki are promoting lightweight, stretchable and quick-drying clothing aimed at office workers. These strategies align with a broader consumer trend: as employers grant greater discretion for dressing down, especially when employees are not meeting clients, the boundary between formal business attire and functional activewear blurs. The result is a growing market for garments that meet workplace acceptability while addressing 35 deg C-plus heat and 72 per cent humidity. Fast Retailing, operator of Uniqlo, has long positioned its AIRism and other functional fabrics for exactly this climate; Aoki, traditionally a suit retailer, is now signalling expansion into business-casual and performance fabrics, a defensive move to offset declining formalwear demand.