Racing in the cold and wet: staying warm enough to still be racing

Cold rain is the condition that ends races for riders who were fit enough to finish them. Not heat, not distance, not the climb everyone worried about. A five-hour road race at 6 °C with steady drizzle produces a finishing field half the size of the same race in the dry, and the difference is almost never fitness.

What makes it dangerous is that the failure is gradual and then sudden. You are cold, then you are quite cold, then you cannot operate the brake lever properly on a descent at 60 km/h. This post is about the physiology of that sequence, and about the decisions — clothing, warm-up, tyre pressure, when to eat — that keep you on the right side of it. For technique and kit on ordinary wet training rides, our piece on riding in the rain is the general guide; this one is about racing, where you cannot simply slow down or turn for home.

Why wet cold is a different problem from cold

Dry cold is manageable because still air trapped in clothing is an excellent insulator and your working muscles produce a great deal of heat. Wet cold removes the first of those. Water conducts heat away from the body far faster than air does, and soaked clothing loses most of its insulating value — so a jacket that was keeping you comfortable at 5 °C stops doing so once it is wet through.

Add movement and it gets worse again. Riding at 35 km/h means a 35 km/h wind across a wet surface, and convective and evaporative losses scale with air speed. Laboratory work on prolonged exercise in simulated rain has shown that the combination of wet skin, wet clothing and air movement can drive core temperature down even while the person is exercising hard — the metabolic heat production of racing is large, but it is not unlimited.

Cold-weather consensus guidance in sports medicine makes the same point in practical terms: the risk factors that matter most are wind, wet clothing and prolonged exposure, and they compound rather than add.

The descent is the dangerous part, not the climb

This is the single most useful thing to understand about racing in the cold, and it catches out experienced riders every winter.

On the climb you are producing a lot of heat, moving slowly, and quite possibly sweating. You feel warm. You unzip. At the top you are wet — with rain, with sweat, or both — and then you descend for ten minutes at high speed, producing almost no heat, with air moving across soaked clothing at 60 km/h. Heat production collapses at the exact moment heat loss peaks.

The practical rule follows directly: put layers on at the top, not at the bottom. Carry a gilet in your pocket up the climb and zip it up over the summit, before you are cold, while there is still warm air inside your jersey to trap. Adding a layer once you are already shivering at the bottom of the descent does very little, because there is no longer any heat to keep in. The descending skills in how to descend faster and safer assume you can feel your hands; in a cold race, that assumption is the thing you have to defend.

What cold does to your hands

Long before you are hypothermic, you lose the ability to operate the bike. This is well quantified in occupational physiology, because the same problem affects anyone working outdoors, and the thresholds are consistent.

Two things follow. The first is that gloves are not a comfort item in a bike race — they are the equipment that keeps you able to brake. The second is that the deterioration is not something you will notice as it happens, because the same cold reduces the sensation you would use to notice it. Test your brakes deliberately early in a descent rather than discovering the problem at the first corner.

Muscle temperature matters too, and in the same direction. Cooled muscle produces less maximal power and contracts more slowly, and neuromuscular function degrades measurably as tissue temperature drops. A sprint at the end of a cold wet race is a worse sprint, and the effect is physiological rather than motivational.

The warm-up needs to be longer and to finish later

Everything that makes a warm-up work — raised muscle temperature, elevated baseline oxygen uptake, faster contraction — decays faster in the cold. A warm-up that would hold for twenty minutes on a mild day may be gone in eight.

So: warm up for longer, do it somewhere sheltered or on a turbo, finish closer to the start, and keep a jacket and an extra layer on until the last possible moment. If you have to stand on a start line in the rain for ten minutes, that time is part of the calculation — a rider who warms up perfectly and then stands soaked in a field for a quarter of an hour has not warmed up. The general principles are in the warm-up, matched to the ride you're about to do; in the cold, err long and err late.

Clothing is a race decision, not a comfort decision

Dress for the effort you will actually make, which in a race is rarely the effort you imagine. A road race with a long neutralised section and a slow first hour needs more than a crit that starts flat out. Over-dressing costs you sweat, which then soaks your inner layers and makes you colder later; under-dressing costs you the race.

If you have someone in the feed zone, a dry base layer handed up mid-race is worth more than it sounds. Wet clothing next to the skin is the main route by which you keep losing heat once you are wet, and swapping the innermost layer restores a large share of the insulation you started with. It costs thirty seconds and it can be the difference between finishing and climbing into a car. Hand up spare dry gloves at the same time. For choosing what to wear at a given temperature more generally, cycling in cold weather has the ranges.

Tyres and the first hour of rain

Wet tarmac has less grip than dry tarmac, and tarmac that has just started raining after a dry spell has less grip than either, because oil and rubber deposits lift off the surface and form a film before the rain washes them away. The first thirty to sixty minutes of a shower after a dry week is the most slippery the road will be all day, and it is when most wet-weather crashes happen.

Drop your pressure. A softer tyre deforms around the surface and gives you a larger contact patch, which is worth more in the wet than the small rolling-resistance penalty costs you. For a 28 mm tyre on wet roads, taking 0.3–0.5 bar off your dry-weather number is a reasonable starting point; our numbers piece on tyre pressure covers how to work out your dry baseline first. Then brake earlier, straighten the bike before you brake, and treat painted lines, drain covers and tram rails as ice, because in the wet they effectively are.

Eating when you cannot open a wrapper

This is a small practical problem that ends races. You need to eat, your hands have stopped working, and gel wrappers are designed for a warm supermarket.

Solve it before the start. Open and half-tear every wrapper in the car park. Decant gels into a flask you can drink from with one hand. Use bigger, simpler food — malt loaf, rice cakes, anything you can grab with a fist rather than pinch with fingers. Put everything in the pockets you can reach without looking down. And set an alarm or a lap timer, because cold suppresses appetite and you will not want to eat, right up until the moment you find out that you should have.

Keep drinking too. It is easy to finish a cold race with a full bottle, and you still sweat under a rain jacket even when you cannot feel it.

Afterwards: get dry fast, and know the red flags

The most dangerous twenty minutes of a cold race are often the twenty minutes after it. You stop producing heat, you are soaked, and you stand about talking to people. Core temperature can keep falling after you stop — so get out of wet kit first and socialise second. Dry clothes, a hat, something warm and sweet to drink, and shelter from the wind, in that order.

Most riders will be shivering and miserable and entirely fine. But cold exposure has a point past which the answer is medical attention rather than another jacket, and it is worth knowing what that looks like, because the affected rider is usually the last person able to judge it.

The judgement call

There is a version of this advice that says toughen up, and it gets people hurt. The honest position is that racing in the cold and wet is a skill with a physiological basis and a real risk attached, and that most of the skill is exercised before the flag drops: what you put on, what you carry, what you hand up, and whether you zip up at the top of the climb rather than the bottom.

The other part of the judgement is knowing when the answer is to stop. A rider who cannot brake properly is not racing any more, and abandoning a wet March road race costs you one result. Carrying on past that point has occasionally cost people considerably more.