Value Village ／ Clothing
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Visitors to Japan in summer often ask why so many people carry a parasol (日傘, higasa) and wear long-sleeved UV-cut clothing in the heat. Blocking UV with fabric has measurable effectiveness, and Japan's Ministry of the Environment has set out how clothing, parasols and sunscreen fit together.
| Measure | Detail |
|---|---|
| UV-shielding rate (紫外線遮蔽率) | The percentage of UV a fabric blocks. Most products sold as "UV-cut" claim 90% or more. Measured under JIS L1925 |
| UPF (the measure used abroad) | UPF 15–50+. UPF 50 = 1/50 of UV (2%) gets through |
| Parasols | Dark colours such as black with a light-blocking rate of 99% or more stop almost all UV reaching the head. They cannot stop reflected UV |
| A plain white T-shirt | UV-shielding rate about 80%. Lower when wet |
| Hats | A brim of 7 cm or more cuts UV to the face by about 60% (Ministry of the Environment manual) |
[Verify] Check the measurement method against JIS L1925 and the UV Index guides against the Ministry of the Environment manual (2020). The figures are general guides.
A UV-cut long sleeve blocks reliably without reapplying sunscreen. In a thin, breathable fabric, because direct sun never reaches the skin, many people find it feels cooler than short sleeves in full sun.
White reflects heat, but tends to let more UV through than dark colours. "Cool" and "shielding" are separate; look for a UV-cut finish.
The Ministry of the Environment recommends parasols for men as a heatstroke measure (public campaign from 2019). The perceived temperature under a parasol is generally described as a few degrees Celsius lower.
Surface-applied finishes decline gradually with washing. Some labels state "up to ○ washes". Finishes built into the fibre are far more durable.
A parasol cannot stop UV reflected from the ground or walls (10–25% is reflected by sand, 10–20% by water, 80% or more by snow). Sunscreen on exposed skin alongside the parasol is the approach in the Ministry's manual.
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https://www.env.go.jp/chemi/uv/uv_manual.html
https://www.jisc.go.jp/
https://www.wbgt.env.go.jp/
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
Follow the care label and the maker's instructions for any garment, shoe or bag. For expensive or sentimental items, ask a specialist cleaner or repairer.
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