What to Wear for a Half Marathon: Race-Day Outfit by Weather, Chafing Fixes, and a Checklist

For a half marathon, wear clothes you have already done a long run in, dressed for a temperature about 15 to 20°F warmer than the start. If you have a race coming up, the rest covers a temperature chart for layers, what to wear on top, on the bottom and on your feet, cold starts, chafing, what to carry, and a checklist for the night before.

Thirteen point one miles is long enough for small clothing problems to become big ones. A seam you barely notice on a 4-mile run can rub skin raw by mile 10, a jacket that felt right in the corral ends up sweat-soaked and tied round your waist, and new socks can give you a blister before halfway. Most of the right outfit is probably already in your drawer. If your shoes are near the end of their life, read our guide on how often to replace running shoes first; no outfit fixes worn-out cushioning.

Nothing new on race day

Every item you wear on race morning should have already done a long run with you, ideally one of 8 miles or more. That includes shoes, socks, shorts, sports bra, shirt, headband, and anything you plan to carry. Long runs reveal what short runs hide: a waistband that slips when it gets wet, a sleeve seam that rubs the underarm, a sock that bunches under the arch.

This rule catches people out at race expos, where it is tempting to buy a new shirt or a fresh pair of shorts the day before. Buy them if you like, but save them for the week after. The same goes for the free race shirt in your goody bag: it has never been washed, you do not know where its seams sit, and a few thousand other runners will be wearing it too.

Do a dress rehearsal on your last long run, two or three weeks out. Wear the complete outfit at roughly the same time of day as your race start, carry your gels in the pockets you plan to use, and note anything that rubs, slides, or bounces. You still have time to fix it.

Dress for mile 3, not the start line

Standing in the corral feels colder than running. Within the first mile or two your body heats up, and a long-sleeve top that felt essential at the start becomes too warm. A common rule of thumb is to dress as if it were 15 to 20°F warmer than the start temperature. It is a starting point, not a law: runners who feel the cold, those running at an easy pace, and anyone racing in wind or rain should lean toward the cooler end of that range.

Use the forecast for your start time, not the daily high, and look at wind and humidity as well as temperature. On a hot, humid morning, MedlinePlus's heat illness advice applies: loose, lightweight, light-colored clothing, and fluids before, during and after the effort.

Rain changes things less than you might think. A light, fitted technical shirt and a cap to keep water out of your eyes beat a rain jacket, which traps heat and stays wet anyway; our guide to running in the rain covers when a jacket does earn its place. Wind does change things: a headwind on an exposed course can make 45°F feel like the 30s, so consider arm sleeves and gloves you can remove. For racing in real cold, our winter running gear guide goes deeper on layering.

Tops, bottoms and socks

Tops

Choose a technical fabric such as polyester or nylon blends, or merino wool for cool races, with flat seams under the arms and across the shoulders. Fit matters more than brand: a shirt that is too loose flaps and rubs, and one that is too tight can chafe under the arms.

For warm races, the Under Armour Iso-Chill Run Short Sleeve uses a cooling fabric with flat-knit construction and reflective details, though its slim, men's cut will not suit every body. For mild and cool days, the Under Armour Tech 2.0 Tee is a basic, budget men's technical shirt with anti-odor treatment and a wide size range; it is less comfortable in real heat. For a women's top, the Under Armour Women's HeatGear Armour Scoop Tank uses super-light HeatGear fabric with mesh ventilation zones and dries quickly, which suits warm races; its compression fit will not suit every body, and sizing runs small, so check the chart. Our moisture-wicking running shirts guide compares more options.

Treat your sports bra as seriously as your shoes. Wear one you have done long runs in, check that the band does not ride up when wet, and put anti-chafe balm along the band line.

Shorts or tights

Shorts suit most half marathons above about 40°F. Look for a waistband with an internal drawcord that stays put when it gets wet, a liner or a tight-fitting design that does not ride up, and at least one secure pocket. Inseam length is personal: split shorts give freedom of movement, while a 5-inch inseam covers more of the inner thigh, where chafing starts.

The Brooks Chaser 5" Running Short is a women's short built around exactly that: DriLayer fabric, a 5-inch inseam for thigh coverage, and an adjustable waistband with storage. It is heavier than some shorts at the same price. See our best running shorts for women for lighter and cheaper alternatives, or browse men's 5-inch running shorts if you need a men's pair.

Tights make sense below about 35 to 40°F, or for runners who chafe no matter what. Choose a pair with a drawcord and a back or side pocket, and make sure they do not sag at the knee when wet.

Socks

Blisters are the most common reason a good race turns into a limp. Wear thin-to-medium synthetic or merino socks that you have run in with your race shoes, never cotton. Trim your toenails a couple of days before the race rather than the night before, so any tender spots have time to settle.

Compression socks are optional. Research on whether they improve race performance is mixed, but some runners like how they feel on long efforts. If you already train in them, the Swiftwick Aspire Twelve is a thin, knee-high compression sock that fits well in snug racing shoes, with minimal cushioning underfoot. If you have never run long in compression, race day is not the time to start. Our compression socks for running guide explains the options.

Cold starts: sleeves and throwaway layers

On a cold morning, start warm and finish light. Instead of a jacket you will carry for 13 miles, use layers you can remove or discard.

Arm sleeves are the most adaptable layer in running. Wear them with a short-sleeve shirt at the start, push them down to your wrists after a mile or two, and pull them back up if the wind picks up. The Nike Pro Dri-FIT Sleeves 4.0 use moisture-wicking fabric with UPF 50+ protection, which also makes them useful on sunny races (the Skin Cancer Foundation says UPF 50 fabric lets through only about 2 percent of UV); the sizing runs small, so check the chart before ordering. Our arm sleeves for running guide covers other picks.

Throwaway layers keep you warm in the corral. An old sweatshirt, a thrift-store fleece, or a pair of cheap cotton gloves works well, because you will shed them once you warm up. Many large races collect discarded clothing along the first miles and donate it; check your race guide for its policy, and toss layers to the side of the course, never in front of other runners. A large trash bag with holes cut for your head and arms makes a free wind and rain poncho for the wait.

Wear gloves below about 45°F. Hands get cold long before the rest of the body, and thin gloves are easy to tuck into a waistband once they come off.

Hats, headbands and sunglasses

A cap or visor keeps sun and rain off your face. A headband keeps sweat and hair out of your eyes, which matters more than it sounds by mile 9. The Lululemon Fly Away Tamer Headband is a sweat-wicking, reversible headband that is soft against the skin; it is pricey for what it is and can leave a mark if worn for hours. Our running headbands guide has cheaper options.

On a sunny course, sunglasses reduce squinting and eye strain. Our sports sunglasses guide covers pairs that stay put when you sweat. Wear sunscreen on your face, shoulders, and the backs of your arms and neck even on cool, bright mornings.

Preventing chafing

Chafing happens wherever wet skin rubs against skin or fabric, and a half marathon gives it plenty of time.

• Put anti-chafe balm on generously: inner thighs, underarms, sports bra band, waistband line and anywhere a seam sits. On long, hot races, top up at medical stations that hand out petroleum jelly.
• Protect your nipples. Men especially should use balm, tape or nipple guards; a sweat-soaked technical shirt rubs hard over 13 miles.
• Cut out tags or choose tagless shirts, and check no seam sits right under the arm.
• Choose snug over loose. Fitted, flat-seamed fabric moves with you; baggy fabric bunches and rubs.
• Skip cotton. It holds sweat, gets heavy and turns abrasive.

After the race, shower promptly and wash your kit; our how to wash workout clothes guide explains how to keep technical fabrics from holding odor.

What to carry

Most runners carry fuel, a phone or key, and sometimes a small card with ID and an emergency contact. Decide where each goes during your dress rehearsal.

Take the gels or chews you trained with, on the schedule you practised. A half marathon takes most runners between 1.5 and 3 hours, so many will want one or two gels. A zip pocket on your shorts or tights, or a slim running belt, stops a phone and key bouncing. Pin your bib to the front of your shirt where it can be seen, or use a race belt if you plan to shed a layer over it.

If your shorts have no secure pocket, browse slim running belts and try one on a long run before the race.

Race-day checklist

Lay everything out the night before, so race morning is only about getting dressed and eating breakfast.

How we chose

Every product here meets four criteria: technical, non-cotton fabric; features that matter over 13.1 miles, such as flat seams, secure waistbands, and pockets; flexibility across a range of race temperatures; and a fair price for what it does. Product details come from each Amazon listing and from our existing category guides to running shirts, women's running shorts, compression socks, arm sleeves, and headbands. Each item was in stock at our latest Amazon listing check on September 11, 2026. This is a buying guide, not a new hands-on review, so fit and comfort still depend on your own long-run rehearsal.

If you need to fill gaps

Buy early enough to try each piece on a long run first. The Under Armour Iso-Chill Run Short Sleeve suits warm races, the Tech 2.0 Tee is the budget shirt for mild weather, and the Women's HeatGear Armour Scoop Tank is a light, quick-drying women's top. The Brooks Chaser 5" is a secure women's short with thigh coverage. The Swiftwick Aspire Twelve is for runners who already like compression, the Nike Pro Dri-FIT Sleeves 4.0 handle cold starts, and the Lululemon Fly Away Tamer Headband keeps sweat out of your eyes.

Frequently Asked Questions

Should I wear shorts or tights for a half marathon?

Shorts suit most races that start above about 40°F, because you warm up quickly. Tights make sense below about 35 to 40°F or if you chafe badly in shorts. Whichever you choose, wear a pair you have already done a long run in.

What should I not wear to a half marathon?

Avoid anything new, anything cotton, and heavy jackets you will end up carrying. Also skip the unwashed race shirt from the expo; its seams and fit are unknown, and there is no time to find out mid-race.

How many layers should I wear for a cold half marathon?

Usually one fewer than feels comfortable standing still. A long-sleeve technical top, or a short-sleeve shirt with arm sleeves, plus gloves and a throwaway layer for the corral, covers most races down to about 30°F. Add a light wind layer below that.

Are compression socks worth it for a half marathon?

They are optional. Evidence that they improve race performance is mixed, but some runners like the supported feel over long distances. Wear them on race day only if you have already run long in them.