Quick summary
- The rule: dress for about 10°C (15–20°F) warmer than the actual temperature, because you'll heat up within the first few kilometres.
- Nothing new on race day: every item should have been worn on at least one long run of 25 km or more.
- Fabric: lightweight, moisture-wicking synthetics or merino. Avoid cotton, which holds sweat and chafes.
- Start-line warmth: wear an old layer you're happy to throw away (many races collect them for charity).
- Pack the small things: anti-chafe balm, bib belt or pins, gels, cap or visor, sunscreen.
Your kit won't make you faster by itself, but the wrong kit can easily make you slower. Chafing, blisters, overheating and shivering in the start pen have ended more good marathons than lack of fitness. The good news is that all of them are preventable with a little planning.
Dress for the second half, not the start line
The most common mistake is dressing for how cold you feel standing still at 7 a.m. Within 10–15 minutes of running, your body produces far more heat. Dress as if it's about 10°C warmer than the forecast, and handle the start-line chill with a throwaway layer.
Check the "feels like" temperature at your expected finish time too. A cool start can become a warm finish by late morning.
What to wear by temperature
| Forecast ("feels like") | Top | Bottom | Extras |
|---|---|---|---|
| Above 18°C (64°F) | Singlet or very light short-sleeve | Split shorts or short shorts | Cap or visor, sunglasses, sunscreen; extra fluids and sodium |
| 12–18°C (54–64°F) | Singlet or short-sleeve | Shorts | Cap; throwaway top for the start |
| 5–12°C (41–54°F) | Short-sleeve, or singlet with arm sleeves | Shorts | Light gloves; throwaway top or bin bag for the start |
| Below 5°C (41°F) | Long-sleeve base layer | Shorts or half tights | Gloves, headband or beanie; throwaway layers |
| Rain at any temperature | Same as above, fitted rather than loose | Same as above | Cap to keep rain off your face; extra anti-chafe |
| Strong wind | Add a light, packable layer if below 10°C | Same as above | Gloves |
Best marathon conditions for most runners are cool: roughly 5–12°C. If race day is warm, adjust your goal pace rather than just your clothing. See our guide to marathon training in hot weather.
The complete race-day checklist
Wear
- Race top (singlet or tee), tested on a long run
- Shorts or tights with pockets or a waistband that holds gels
- Running socks, synthetic or merino, tested on a long run
- Race shoes with at least 30–50 km of running in them (not brand new)
- Sports bra, if you wear one, tested on a long run
- Cap or visor, sunglasses (if sunny)
- GPS watch, charged
Carry
- Race bib, pinned to the front, or a bib belt
- Gels or chews for your fueling plan, plus one spare
- Anti-chafe balm (also apply before the start)
- Phone (optional), in a pocket or belt that doesn't bounce
Start-line bag
- Throwaway layer: old top, bin bag or space blanket
- Toilet paper or tissues
- Water or sports drink to sip before the start
- Gel for 15 minutes before the start
- Sunscreen, applied before you leave
Bag-drop or finish bag
- Dry, warm clothes and a jacket
- Comfortable shoes or sandals
- Recovery drink or snack
- Phone charger, payment card, travel or transport plan home
How to prevent chafing and blisters
Chafing comes from skin rubbing against skin or fabric, made worse by sweat, salt and seams.
- Apply anti-chafe balm before the start to the inner thighs, underarms, sports-bra line, waistband and feet.
- Nipple chafing is common in men over long distances: use plasters or nipple guards.
- Choose fitted, seam-light fabrics. Loose, heavy or wet cotton is the main culprit.
- If something rubs slightly on a 25 km long run, it will rub badly at 35 km in the race. Change it before race day.
Blisters come from friction, moisture and poorly fitting shoes or socks.
- Race in shoes you've run at least 30–50 km in, and that fit with a thumb's width in front of your longest toe.
- Wear synthetic or merino socks, not cotton.
- Trim toenails a few days before the race, not the night before.
- Tie laces snugly enough to stop your heel slipping, without pressure on top of the foot.
Race shoes: new or old?
Race in a pair you trust. That means shoes you've worn on at least one long run and a marathon-pace session, but which are not worn out. Most running shoes lose cushioning gradually over several hundred kilometres. If you want a new pair for race day, buy it at least three to four weeks before, and run your last long runs in it.
The night before
- Lay everything out, including your bib, gels and safety pins.
- Pin your bib to your top so it's ready.
- Charge your watch and phone.
- Check the race-morning forecast one last time and pick your layers.
- Set two alarms and plan to arrive 60–90 minutes before your start time.
FAQ
What should I wear for a marathon in cold weather?
Below about 5°C, most runners wear a long-sleeve base layer, shorts or half tights, gloves and a headband or beanie, plus throwaway layers for the start. Dress lighter than feels comfortable at the start line, because you'll warm up quickly.
Should I wear a singlet or a t-shirt for a marathon?
Either works if you've tested it. Singlets are cooler and chafe less under the arms in warm weather; short-sleeve tops are better on cool or sunny days if you burn easily.
Is it OK to wear new shoes for a marathon?
It isn't recommended. Race in shoes you've worn for at least 30–50 km, including a long run, so any blister or fit problems show up in training rather than on race day.
How do I stop my thighs chafing during a marathon?
Apply anti-chafe balm to the inner thighs before the race, wear fitted shorts or half tights in a smooth synthetic fabric, and test the combination on a long run of 25 km or more.
What is the ideal temperature for running a marathon?
Most runners perform best in cool conditions, roughly 5–12°C (41–54°F). Above about 15°C, most runners slow down as temperature rises, especially in high humidity.
Product and kit choices are personal; test everything on long runs and stop if anything causes pain or skin damage.