The pick for a light running cap is mont-bell's WIC.Cool Light Cap: 29g with a 6.0cm brim. For summer fulls and halves, this; for trails, The North Face Swallowtail Cap (about 30g); for rainy days, mont-bell's Reflec Cap with a 7cm brim; for winter training, mont-bell's Merino Wool Plus Light Watch Cap (22g). These are answers by scene, compared on official numbers.
The Shoe Nerd's top pick
Choose a cap not by the 4 words "UV cut" but by the number that follows. UPF 50+ lets through 1/50 of UV, and blocking of 90% or more lets through up to 1/10. They look like the same words, but there is a 5-fold gap. For a race where you are in the sun for 3 hours or more, I would give up 16g of lightness and switch to The North Face GTD Cap, which says UPF 50+.
Key points
- The lightest of the 12 is mont-bell's visor at 18g and the heaviest is On's 58g. A 40g gap
- mont-bell is the one that writes brim length officially. From 5.5cm to 7cm, a 1.5cm spread
- Sweat control comes in 2 ways: a build that "absorbs" and one that "changes the flow." On is the former, GUTR the latter
"UV cut" written on it did not mean they were all the same
Running cap product pages usually say "UV cut." But read the number after it and the contents split into 2 kinds: "UPF 50+" and "UV blocking rate 90% or more."
The two differ by 5 times in the amount of UV let through (the calculation is in a section below). Weight also varied, even within the same "lightweight cap," from 29g to 58g, a 2-fold spread.
So I sort 12 into 4 types by material, weight, UV notation, how to fit the size and price on the Japan official sites. After that, I pick one for each scene.
How to choose a running cap: the conditions I used
It is not in order of sales. I compared only official numbers on the following 4 conditions.
| Criteria | Reason |
|---|---|
| (1) The weight is written officially | The lighter the thing on your head, the less you notice it |
| (2) The UV notation has a number | You cannot compare with the words "UV cut" alone |
| (3) You can tell how to fit the size | It lifts in the wind when you run. Whether you can tighten it |
| (4) Price | A consumable that wears out with sweat and washing |
When ranking, I put models that show (1) to (3) with official numbers higher.
(1) Weight of the 6 running caps (with a brim)
| Model | Weight | Official price |
|---|---|---|
| mont-bell WIC.Cool Light Cap | 29g | JPY 3,800 |
| mont-bell Reflec Cap | 41g | JPY 3,300 |
| The North Face GTD Cap | About 45g | JPY 4,510 |
| The North Face Swallowtail Cap | About 30g | JPY 6,050 |
| On Lightweight Cap | 58g | JPY 6,380 |
The gap between the lightest, the WIC.Cool Light Cap, and the heaviest, On, is 29g (58 − 29). On is exactly 2 times.
Even within mont-bell, the brims are 6.0cm and 7cm, a 1cm difference.
Image: Rakuten Ichiba
mont-bell WIC.Cool Light Cap
Lowest price on Rakuten Ichiba: JPY 4,800 (as of 10/13). Prices change daily.
RecommendedSee it on Rakuten Ichiba(2) How many g lighter are the 2 sun visors than a cap?
Scroll the table sideways →
| Model | Weight | Brim | UV notation | Official price |
|---|---|---|---|---|
| mont-bell WIC.Cool Light Visor | 18g | 6.2cm | Blocking rate 90% or more | JPY 2,500 |
| mont-bell Trail Headband with Visor | 31g | 6cm (with a core) | Blocking rate 90% or more | JPY 2,500 |
A visor has no fabric over the top of the head. Compared with the cap of the same ultra-thin fabric (29g), it is 11g lighter (29 − 18). As a share, about 38% (11 ÷ 29). The price falls JPY 1,300 too (3,800 − 2,500).
In exchange, the top of your head stays out in the sun. For people with thinning hair or who worry about their part, this is the reason to choose a cap.
(3) 2 hats with a neck flap
Scroll the table sideways →
| Model | Weight | Brim | Flap / cord | Official price |
|---|---|---|---|---|
| mont-bell WIC.Cool Light Shade Cap | 45g | 5.5cm | With a screen that protects the neck | JPY 4,800 |
The shade cap is the same ultra-thin fabric as the WIC.Cool Light Cap in (1). The weight gap is 16g (45 − 29) and the price gap JPY 1,000 (4,800 − 3,800). The brim length differs by 0.5cm so it is not exact, but the one neck flap is roughly 16g and JPY 1,000.
It is the type for people who want a shadow on the back of the neck on sunny ridges or at turnarounds on the road.
Image: Rakuten Ichiba
mont-bell WIC.Cool Light Shade Cap
Lowest price on Rakuten is JPY 5,800 (as of 10/13), ranging up to JPY 6,980 depending on the shop. Prices change daily.
RecommendedSee it on Rakuten Ichiba(4) 2 winter beanies and headbands
Scroll the table sideways →
| Model | Weight | Material | Covers | Official price |
|---|---|---|---|---|
| mont-bell Merino Wool Plus Light Watch Cap | 22g | 78% wool + 22% polyester | Head and ears | JPY 3,100 |
| mont-bell Chamois Headband | 16g | Chamois (polyester) | Forehead and ears | JPY 1,700 |
Winter hats come in lighter ones than summer. The watch cap's 22g is lighter than any of the 6 summer caps. A headband is 6g lighter still and JPY 1,400 cheaper (22 − 16, 3,100 − 1,700).
What a cap's UPF number means
This is what I most want to get across in this article.
mont-bell's official page explains UPF like this: short for Ultraviolet Protection Factor, an index showing how well clothing blocks UV. UPF 50+ shows it delays the time until sunburn by 50 times or more compared with wearing nothing.
Delaying by 50 times means the fabric lets through 1/50. Calculating, 1 ÷ 50 = 0.02. It lets through up to 2% and stops the remaining 98%. The "UV blocking rate 98% or more" that mont-bell adds to its UPF 50+ visor is the same number as this division.
Then what about "UV blocking rate 90% or more"? It lets through up to 10%. 2% versus 10%. Compared by amount let through, that is a 5-fold gap (10 ÷ 2).
| Official notation | Amount stopped | Amount let through | Models with this notation |
|---|---|---|---|
| UPF50+ | 98% or more | Up to 2% | The North Face GTD Cap |
| UV blocking rate 90% or more | 90% or more | Up to 10% | mont-bell's WIC.Cool Light Cap, Reflec Cap and visor |
There is one more small note. mont-bell attaches a note that the blocking rate "differs with the shade of the product's color, its construction and specifications." The Reflec Cap also carries the line "excluding the mesh parts."
In other words, the bigger the mesh area of a cap, the narrower the range where the number applies. Holes that let wind through let light through too. Coolness and sun protection compete over the same fabric.
Brim stiffness, and whether it folds
There are 4 models where the brim's build is known.
- The North Face Infinity Trail Cap (about 30g, JPY 7,150): the official feature says "soft brim."
- mont-bell Trail Headband with Visor: the brim has a core and its shape can be changed freely.
- HALO Halo trail 2 (JPY 6,600): wire built into the brim. You can wear it with the brim stood up.
- ELDORESO Sanskirt Jet Cap (JPY 7,700): the brim is 4.5cm. The official explanation is that a short brim secures a wide field of view on uphill trails and makes it easy to put a headlamp on over the cap.
Brim length has a direction. The longer it is, the more shadow on the face; the shorter, the more you see upward. mont-bell's 7cm versus ELDORESO's 4.5cm is a 2.5cm difference (7 − 4.5). Longer for sunny roads, shorter for trails where you look up ahead on climbs. Lined up with the official explanations, that is how it comes out.
If you intend to stuff it in a pocket partway through a race, choose from the Infinity Trail Cap with its "soft brim" or the brimless headband types.
The sweatband: absorb, or change the flow
The band on the inside of a cap that touches the forehead is the sweatband. Reading the official explanations, there are 2 builds.
One is a build that absorbs. On's Lightweight Cap explains its inner sweatband absorbs sweat quickly. The body is 100% polyester, and only the sweatband is 60% polyamide, 27% polyester and 13% elastane. Only the band is a different cloth. mont-bell's Trail Headband with Visor also writes that the headband part acts as a sweatband.
The other is a build that changes the flow. The GUTR Sweatband FLEX (17g) carried by mont-bell's official store is explained as changing the direction sweat runs with a rail on the forehead, preventing sweat from getting in your eyes. HALO writes "sweat block seal included" on its headband and "silicone rubber on the inside" for the Halo trail 2.
An absorbing band drips once it passes what it can absorb. A flowing band does not absorb, so there is no upper limit. The longer you run, the more worth looking at the latter build.
How to fit a running cap's size
| Model | Sizes | How to fit |
|---|---|---|
| mont-bell WIC.Cool Light Cap | S, M, L | Choose from 3 sizes |
| mont-bell Reflec Cap | S, M, L | Back adjuster |
| The North Face GTD Cap | M, L | Stretch buckle |
| The North Face Swallowtail Cap | M, L | Drawcord |
| On Lightweight Cap | Free | Buckle with a logo |
| HALO Halo trail 2 | Free | Pull the cord at the back |
| ELDORESO Sanskirt Jet Cap | S (54 to 57cm), M (57 to 60cm) | Adjuster belt at the back |
Models you tighten with a cord or buckle can be fixed with one hand while running. Models that fit by size alone mean measuring your head circumference before buying. One tape measure is enough.
The lighter the cap, the higher the price per gram
I worked out how much you pay for lightness as official price ÷ weight.
| Model | Weight | Official price | Per gram |
|---|---|---|---|
| mont-bell Reflec Cap | 41g | JPY 3,300 | About JPY 80 |
| The North Face GTD Cap | About 45g | JPY 4,510 | About JPY 100 |
| On Lightweight Cap | 58g | JPY 6,380 | About JPY 110 |
| mont-bell WIC.Cool Light Cap | 29g | JPY 3,800 | About JPY 131 |
| mont-bell WIC.Cool Light Visor | 18g | JPY 2,500 | About JPY 139 |
| The North Face Swallowtail Cap | About 30g | JPY 6,050 | About JPY 202 |
The lighter the cap, the higher the price per gram. Even if you cut fabric, the sewing labor does not shrink. That is how I read it. The Swallowtail Cap was about 2.5 times the Reflec Cap (201.7 ÷ 80.5).
But seen by total price, the story reverses. The lightest cap (JPY 3,800) is JPY 2,580 cheaper than the heaviest, On (JPY 6,380). A light cap is not necessarily an expensive one.
The pick for each scene
Summer full marathon and half: mont-bell WIC.Cool Light Cap
Why this one: Because among caps with weight, brim length and UV notation all written officially, it is the lightest. 29g with a 6.0cm brim. mont-bell explains that knitting the fabric very thin keeps heat from building up. It also has reflective material at the front and sides.
In spring to early summer halves, races sometimes require a cap. The Gifu Seiryu Half's participation guide does (article on the half marathon pace table and cutoffs). As the first item for my packing list, I choose this.
Watch out: The UV notation is "blocking rate 90% or more." You choose from 3 sizes, S, M and L, so measure your head circumference before buying.
Who should switch: People who spend 3 hours or more in the sun. Make it the GTD Cap, which says UPF 50+. It is 16g heavier (45 − 29), but the upper limit of what it lets through is one fifth.
Image: Rakuten Ichiba
The North Face GTD Cap
Lowest price on Rakuten is JPY 3,111 (as of 10/13), ranging up to JPY 4,620 depending on the shop. Prices change daily.
RecommendedSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanTrail (sun and branches): The North Face Swallowtail Cap
Why this one: Because it is an about-30g cap whose official "recommended scenes" line up 3: mountaineering, trail running and running. The fabric is 100% woven nylon with a water-repellent finish (DWR). On the sides are ventilation windows that cut stuffiness. Size is tightened with a drawcord.
The front panel is woven fabric, not mesh, so it has no holes. On a path that ducks under trees, choosing a front without holes is why I separate it from the mesh-leaning road caps in (1).
Watch out: Price per gram is the highest of the 6.
Who should switch: People on courses that go long along sunny ridges after leaving the forest. Make it mont-bell's shade cap with the neck flap (45g). For a race that runs into the night, where you put a headlamp on over the cap, the ELDORESO Sanskirt Jet Cap with its 4.5cm brim is a candidate. Whether a cap is mandatory gear differs by race (article on trail mandatory gear).
Image: Rakuten Ichiba
The North Face Swallowtail Cap
Lowest price on Rakuten is JPY 3,930 (as of 10/13), ranging up to JPY 6,050 depending on the shop. Prices change daily.
RecommendedSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanRainy days: mont-bell Reflec Cap
Why this one: Because the brim is 7cm, the longest of the caps that write the length officially. The body is 40-denier nylon taffeta with a water-repellent finish. The sides are mesh. It has ink printed that reflects when car lights hit it, and mont-bell writes that it suits night running. Rainy days are dark, so this works there too.
The official price is the lowest of the 6 caps, and also the lowest per gram (table above). It sits just right as a pick you expect to get wet and dirty.
Watch out: Water repellency is a finish that sheds water, not waterproofing. The weight is 41g, 12g heavier than the WIC.Cool Light Cap (41 − 29).
One suited to rain: The North Face Trail Peak Cap (about 35g) uses the waterproof breathable material FUTURELIGHT on the brim and forehead and can handle rainy weather. But on Oct 13, 2026, the official store treated it as outlet and all sizes were out of stock.
Winter training: mont-bell Merino Wool Plus Light Watch Cap
Why this one: Because it is light at 22g and how it releases sweat is written officially. A 2-layer knit with fast-drying polyester added on the skin side of merino wool fabric. mont-bell explains it keeps the wool's warmth, dries sweat quickly and keeps the skin side dry.
What troubles you in a winter hat is the sweat after you start running and warm up. Choose not a thick knit that is just warm, but a build that dries on the skin side. That is why I narrowed the many winter hats to this one.
Watch out: The official care notes say it shrinks somewhat after washing and color can transfer when wet and rubbed. Washing it apart from other clothes takes effort.
Who should switch: People whose heads get hot easily. Make it the Chamois Headband (16g) that covers only the ears and forehead. The top of the head is open, so a route for heat to escape remains.
People who choose On and Nike
On's Lightweight Cap is 58g, the heaviest of the 6, and has no UV number. The reason to choose it anyway is the sweatband. It was the only cap with the band's material written officially. It has ventilation holes on the sides and a reflective logo at the front. On writes that it suits speed-focused scenes like the road and the track.
For people who match shoes and apparel in On, it is a pick with nothing to hesitate over (article on recommended running apparel).
Image: Rakuten Ichiba
On Lightweight Cap
Lowest price on Rakuten is JPY 5,742 (as of 10/13), ranging up to JPY 6,380 depending on the shop. Prices change daily.
RecommendedSee it on Rakuten IchibaSee it on Yahoo! Shopping JapanNike's Fly Cap comes in 2 types. The difference is the side panels.
- Dri-FIT ADV Fly (FJ0736, official JPY 6,270): AeroAdapt panels on the sides. Vents that react to sweat and keep temperature. The body is 100% polyester and the panels 81% polyester and 19% nylon. Tightened with a drawcord and toggle.
- Fly Dri-FIT (FB5624, official JPY 4,400): body and lining both 100% polyester. Tightened with a mesh strap.
The price gap is JPY 1,870 (6,270 − 4,400). For summer races where you sweat a lot, the ADV; for everyday use that doubles as the gym, the plain one. Neither shows a weight or UV number, so if you compare by numbers, there are other ways to choose.
Who is it for?
- Good fit: People who run during daylight hours. The brim works as a sunshade.
If you run only before sunrise or in the evening, even a thin headband that absorbs sweat will do. If you have a summer cap and winter training is about 30 minutes, a JPY 1,700 headband is enough. The gap between a visor and a cap is 11g. Whether you want the top of your head out or covered decides which 1.
The weak points of this article
The weight conditions are not matched across makers. mont-bell is average weight, The North Face is size L, and On is one size. A difference of a few grams is buried in the difference in conditions.
FAQ
What is the difference between UPF 50+ and UPF 50?
The "+" means it exceeds 50. In mont-bell's explanation, UPF 50+ shows that it delays sunburn by 50 times or more. In terms of the amount let through, that is less than 1/50 (2%).
Which is lighter, a running cap or a visor?
The visor. With the same ultra-thin mont-bell fabric, the cap is 29g and the visor 18g, 11g lighter. It is JPY 1,300 cheaper too. The top of your head is not covered.
Does the UV number change between a black and a white cap?
It can. mont-bell attaches a note that the blocking rate differs with the shade and construction of the product. Even so, it writes 90% or more for white fabric too. 90% means the lower limit in the least favorable color.
Can a running cap be machine washed?
It differs by model. For On's Lightweight Cap, the official label is hand wash only. mont-bell writes that caps get dirty easily with sweat and sebum and recommends regular washing. Looking at the care field on the product page before you buy saves trouble later.
Gear in this article
Ads and images: Rakuten IchibaSources
- mont-bell official: WIC.Cool Light Cap (#1118686)
- mont-bell official: Mesh Cap (#1118795)
- mont-bell official: Reflec Cap (#1118800)
- mont-bell official: WIC.Cool Light Visor (#1119148)
- mont-bell official: Trail Headband with Visor (#1119147)
- mont-bell official: WIC.Cool Light Shade Cap (#1118779)
- mont-bell official: WIC.UV Tect Visor Detachable Shade (#1119149; UPF explanation)
- mont-bell official: Merino Wool Plus Light Watch Cap (#1119110)
- mont-bell official: Chamois Headband (#1119106)
- mont-bell official: headband list (explanation of the GUTR Sweatband FLEX)
- The North Face official: GTD Cap (NN42513)
- The North Face official: Swallowtail Cap (NN02603)
- The North Face official: Infinity Trail Cap (NN02602)
- The North Face official: Trail Peak Cap (NN42512)
- On Japan official: Lightweight Cap
- NIKE Japan official: Nike Dri-FIT ADV Fly Unstructured AeroBill AeroAdapt Cap (FJ0736)
- NIKE Japan official: Nike Fly Dri-FIT Unstructured Swoosh Cap (FB5624)
- HALO headband Japan official: Halo trail 2
- HALO headband Japan official: Halo hat3
- ELDORESO official: Sanskirt Jet Cap
Related reading
Shoes & gearHow to Buy Japanese Running Shoes Overseas: Sizes, Duty, ShippingFour ways to buy Japanese running shoes from overseas: Rakuten forwarding, buying agents, local stores and shop-to-abroad shipping. How cm sizing works, US and Taiwan duty, banned items, from official pages.Oct 19, 2026
