Thirteen point one miles is an awkward distance to dress for. Long enough that a bad decision at mile two has become a personal grievance by mile ten. Short enough that you talk yourself into believing it does not matter much. It does. Not in a wind-tunnel, marginal-gains way — nobody is taking four minutes off a 2:18 half by switching tops. But there is a version of your race where you spend the back half quietly furious at your own clothing, and a version where you never think about it once.
The second one is available to absolutely anyone. It mostly involves making the decisions the week before, rather than at 6:40am in a Premier Inn with the curtains open, holding two t-shirts and no strong feelings about either.
Dress for the race, not the car park
The single most common race-day mistake is dressing for how it feels while you are standing still, shivering, clutching a coffee you do not really want.
Add about 5 to 10°C in your head
The old coaching rule is to dress for conditions roughly five to ten degrees warmer than the forecast, and it has survived this long because it is broadly correct. Running generates a serious amount of heat, and most of it has to go somewhere. Within fifteen minutes of the gun, a damp 8°C morning is behaving, as far as your body is concerned, like a mild spring afternoon.
So a British autumn half — the Great North Run being the obvious one, 63,000 runners going from Newcastle to South Shields in September — is almost always a shorts-and-short-sleeves race, whatever the sky is doing at 8am. A March race like the Bath Half is the same, with more swearing at the start.
You are supposed to be a bit cold in the pen
If you are warm and comfortable standing in the start pen, you are overdressed and you will find out about it at mile four. Slightly cold, mildly regretting your life choices, wondering whether the long-sleeve was the wrong call — that is the correct sensation. Forty minutes of standing about is not the race. The race is the bit afterwards, when you are producing heat like a small industrial appliance.
The kit list, top to bottom
Nothing here is exotic. The point of a half marathon kit list is that every item on it should be boring to you by race day.
The top
Technical fabric, short sleeves, and — this is the whole trick — one you have already run at least a couple of long runs in. Cotton holds water and then holds it against you for two hours. A race t-shirt you were handed in the goody bag the night before is not a top, it is a trap. Wear it to the pub afterwards like everyone else.
The shorts
Whatever length you already trust. There is no medal for a shorter inseam and no penalty for a longer one, and the only question that matters is whether the leg rides up when you are tired and your form has gone. Check you can get a gel in and out of the pocket without stopping — a lot of shorts pass the standing-still test and fail the mile-nine test.
The socks
Thirteen miles is comfortably far enough for a seam to become the main character. Proper running socks, fitted to the foot, worn in. Not the thin black ones from a five-pack that live in the same drawer. If you have ever finished a long run and found something unpleasant on a toe, this is the cheapest fix available to you.
The cap
Optional right up until it is not. A cap keeps rain out of your eyes, which in this country is the more common problem, and sun off your head on the rare morning it turns up. If you do not like caps, do not wear one. Nobody is checking.
The bits nobody photographs
Anti-chafe balm on everything that rubs, applied generously and twice. Plasters where you know you need them. Safety pins that are not the four bent ones in the bottom of your bag. If you wear a sports bra, race day is not the morning to try the new one. Obvious, and roughly half of every start pen gets it wrong.
Race morning and the bin bag question
You will be cold for an hour and warm for two. The standard solution is a throwaway layer: an old jumper from the back of the wardrobe, or a bin bag with holes cut in it, worn in the pen and abandoned at the start. Most big UK races collect what gets dropped and pass it to charity, which turns a genuinely ridiculous look into a mildly virtuous one.
Lay it all out the night before. Number pinned, gels in pockets, socks inside shoes. Race morning is not a moment for decisions.
What we would actually wear
For a British half in anything between about 6 and 15°C: the Agony Running Tee, which is light enough to stop being noticeable about four minutes in, and the Suffer Running Shorts, which have a pocket that works while moving. Add Blister Running Socks because the name is a promise rather than a description, and the Brow Mop Running Cap if the forecast has any opinions at all. The whole lot lives in The Kit, and if you would rather not think about any of this again, there is The Full Kit.
Common questions
What should I wear for a half marathon in the UK?
For most British races, most of the year: a technical short-sleeve top, running shorts, proper running socks and shoes you have already put serious miles into. Add a cap for rain or sun, and a throwaway layer for the start pen. Dress for about five to ten degrees warmer than the forecast, because that is roughly what your body will experience once you are moving.
Can I wear a new top on race day?
You can, and a fair number of people spend the last five miles discovering exactly where the seams sit. Anything touching your skin for two hours should have done at least one long run first. The expo t-shirt is for afterwards.
Do I need a running cap for a half marathon?
No. It is genuinely useful in rain and in sun, and pointless in still grey nothing-weather, which is most of the time. Check the forecast on the Friday and decide then rather than treating it as a permanent part of your identity.
What do I wear for a half marathon in the rain?
Broadly the same as you would in the dry, plus a cap with a peak. A waterproof jacket at half marathon effort turns into a portable sauna within a mile — you end up just as wet, but warmer about it. Accept being rained on. Put a dry top in your bag drop for the finish, which is the bit that actually makes the difference.
How do I stop chafing during a half marathon?
Balm on the usual places before you start, kit that fits properly rather than loosely, and no brand-new fabric against skin. Thirteen miles is far enough for a small rub to become a large one, and a hot shower afterwards will let you know precisely where you went wrong.
Related reading
If the race is close, what to do in race week covers the seven days where most people manage to make themselves slower. If it is further off, the half marathon training plan for slow runners is built for people finishing somewhere north of two hours. And for the specific misery this article keeps circling, there is how to stop chafing.
Wear the boring clothes. Suffer every mile. Still no medals.