What Is UPF Clothing? How Sun-Protective Fabric Works

You've probably seen "UPF 50+" on a jacket or t-shirt label and wondered what it actually means. UPF clothing is one of the simplest, most reliable ways to protect your skin from the sun, especially on long runs, outdoor training and days when sunscreen sweats off. Here's what UPF is, how it differs from SPF, what makes a fabric sun-protective and how to choose the right UV protection layer.

UPF Explained in Plain Language

What the UPF rating measures

UPF stands for Ultraviolet Protection Factor. It measures how much ultraviolet (UV) radiation a fabric lets through to your skin. Unlike sunscreen ratings, UPF covers both main types of UV that reach us: UVA, linked to skin ageing, and UVB, the main cause of sunburn. 

The number tells you what fraction of UV gets through. A fabric rated UPF 50 allows roughly 1/50th of UV radiation to pass, which means it blocks about 98%.

What UPF 50+ means

UPF ratings are usually grouped like this:

 UPF Rating

Protection Category

Approx. UV Blocked

15-24

Good

93-95.9%

25-39

Very Good

96 - 97.4%

40 - 50 +

Excellent

97.5% or more

UPF 50+ is the top of the scale. For everyday outdoor activity, it's the rating to look for.

UPF vs SPF: What's the Difference?

SPF (Sun Protection Factor) applies to sunscreen and mainly measures protection against UVB. UPF applies to fabric and measures protection against both UVA and UVB.

The practical difference is consistency. Sunscreen needs to be applied evenly and reapplied, and sweat, water and towelling wear it off. A UPF-rated garment protects the skin it covers for as long as you wear it. The two work best together: UPF clothing for covered areas, sunscreen for your face, neck and hands.

What Makes a Fabric Sun-Protective

Weave, weight and fibre

UV passes through the tiny gaps between yarns. Tighter weaves and denser knits leave fewer gaps, so they block more UV. Synthetic fibres like nylon and polyester tend to perform well because they can be woven tightly while staying light. That's how a thin jacket can still earn a high UPF rating.

Colour and fit

Darker and more saturated colours generally absorb more UV than pale ones. Fit matters too: fabric stretched tight over the body opens up the weave and can let more UV through, so a garment that fits comfortably will keep its protection better than one pulled taut.

Finishes and treatments

Some fabrics get extra help from UV-absorbing finishes applied during manufacturing. Whether protection comes from the fabric's structure or a finish, a proper UPF rating means the finished fabric has been tested.

When to Wear UPF Clothing

Running and outdoor training

Long runs, outdoor workouts and sports like golf can mean hours in direct sun. A light UPF layer protects your arms and shoulders without relying on sunscreen that sweats off. Choose fabric that's also breathable and quick drying so you stay comfortable.

Travel, commuting and high altitude

UV is stronger at altitude and reflects off water, sand and snow. A packable UPF jacket is a smart layer for treks, beach days and sightseeing. It's equally useful on daily commutes, especially if you ride a bike or scooter with your arms exposed.


How to Care for UPF Clothing

  • Wash in cold water on a gentle cycle with a mild liquid detergent.
  • Skip bleach and fabric softener, which can affect fabric performance.
  • Dry flat or on a hanger, away from high heat.
  • Replace garments that are visibly thin, stretched or damaged, since worn fabric can let more UV through.

Choosing a UV Protection Jacket

A good UV protection jacket should do more than block the sun. Look for:

  • A confirmed UPF rating on the label or product page, ideally UPF 50+.
  • Lightweight, breathable fabric so you don't overheat.
  • Stretch for running, reaching and everyday movement.
  • A water-repellent finish so the same layer handles a passing shower.
  • Colourfast construction so the colour holds up to sun and washing.

The VYO UV Protection & Water-Repellent Jacket is built around these needs: 150gsm crinkle woven fabric in 87% nylon and 13% spandex, UPF 50+ sun protection, a water-repellent finish, colourfast construction and YKK zips. Explore the full range of UV protection jackets, including women's lightweight jackets and men's lightweight jackets.


FAQs


1Q. What is the best fabric for running in hot weather?

Lightweight polyester or nylon blends, ideally with some spandex. They wick sweat, dry quickly and stay light, unlike cotton, which holds moisture.

2Q. Is it better to run in a singlet or a t-shirt in the heat?

A singlet allows more airflow and is best when heat is the main challenge. A t-shirt offers more sun coverage. Choose based on whether heat or sun is the bigger issue on your route.

3Q. Should I wear long sleeves running in hot weather?

Only if they're thin, breathable and quick-drying. A lightweight long sleeve can protect your arms from strong sun and still keep you comfortable.

4Q. What colour clothes should I wear running in the heat?

Lighter colours reflect more sunlight and tend to feel cooler in direct sun. Darker colours absorb more heat.

5Q. How do I stop chafing when running in hot weather?

Wear synthetic, quick-dry fabrics with smooth seams, make sure your kit fits well, use an anti-chafe balm on hot spots and change out of wet clothes soon after your run.

6Q. Do I need a jacket for hot-weather running?

Not usually, but a very light, packable jacket is useful at dawn, in wind or rain, or for sun protection on exposed routes.

Back to blog