What to Wear Cycling Calculator

What should I wear cycling at each temperature?

Start from the air temperature and dress to feel slightly cold for the first ten minutes. Your body takes that long to get its heat production up to riding pace, and a rider who's comfortable standing in the driveway is overdressed by the first hill. The chart below is the consensus of club and coaching guidance, condensed to what goes on each part of you:

Bands assume a typical road ride: about 16 mph, endurance effort, dry roads, light wind. That assumption is printed in no chart we could find, and it's the one the calculator moves: your speed, the wind, effort and rain shift which band you should be dressing from.

How cold does it feel on a bike? Cycling wind chill by speed

On a bike, you make your own wind. A 35 °F morning at 16 mph feels like 24 °F on your face — the same heat loss from exposed skin as standing still in a 20 mph forecast wind at 35 °F. That's what the grid above prints: the National Weather Service wind chill, fed your riding speed instead of the forecast's wind. It describes exposed skin, which is why it matters most for your face, ears and fingers, and hardly at all for a torso under a windproof jacket.

The surprise is how little speed matters. At 40 °F, riding at 15 mph feels like 31 °F; riding at 25 mph feels like 28 °F. Ten mph more wind moves the number by only 3 °F, because the formula raises wind speed to the 0.16 power — the first few mph of wind do most of the damage and the rest barely register. Wind chill is a big deal the moment you start moving, and then a small one.

Why do some cycling wind chill charts say it's much colder?

Because they're still using the old formula. Before 2001, the US and Canada used the Siple–Passel index from 1945, which was built on how fast water froze in a plastic cylinder on an Antarctic expedition and overstated the chill badly at bike speeds. The replacement was built from a heated model head and volunteers walking on a treadmill in a cold chamber, with wind on their faces. Cycling charts copied from old sources still run the 1945 numbers:

Still air. The old index reads 9–15 °F colder than the current one over these rides — a full kit band, sometimes more. If a chart says 40 °F at 15 mph feels like the low 20s, it's running the 1945 formula.

Commuting vs training: same morning, different kit

If speed hardly matters to wind chill, what does move your kit? Effort and water. Pedaling hard makes a lot of heat, rain carries it away, and both are bigger than anything the wind does. Here's one 35 °F morning for five different rides:

Speed shift computed from the wind chill difference against the chart's 16 mph reference (below 50 °F only). Effort shift is a rule of thumb — easy −5 °F, tempo +5, hard +10 — in line with the 3–6 °C nudges coaching guides use. Rain: one band (10 °F) colder.

The spread across one morning is 22 °F of dressing temperature. The slow commuter feels the least wind but makes the least heat, and the rain puts them into winter kit on a day the racer handles in a thermal jersey. Two of the five riders belong in a different band from the one the thermometer picks — a spread no chart keyed on air temperature alone can see.

Why do I freeze on descents?

Everyone blames the wind, and the wind does pick up. But look at what the wind chill actually does as the speed climbs — here's a 40 °F day and the coasting speed on each grade, computed by our physics engine (165 lb rider, 19 lb bike, on the hoods, no brakes):

Martin power model at the day's air density, zero pedaling, still air. Real descents with corners and brakes run slower; this is the ceiling.

Climbing a hill at 9 mph, the air on your face feels like 34 °F. Coasting down a 3% grade at 23 mph it's 29 °F, and nearly doubling that speed on a 10% descent takes off only another 4 degrees. Past the first 20 mph or so, the wind chill barely changes. What changes is you.

What to wear cycling in the rain

Dress one band colder. Water conducts heat away many times faster than air, and wet fabric loses most of its insulation, so a 55 °F rain ride is a 45 °F ride for your kit. Keep the core in layers that stay warm wet (wool or synthetic, never cotton), put the waterproof money into gloves and shoe covers before the jacket, and fit fenders if you commute — road spray soaks your legs and feet long before the rain gets through your jacket. A fully waterproof jacket on a hard ride is a sauna; a light water-resistant shell you can vent is warmer in practice, because you stay drier from the inside.

Hands, feet and ears go first

Your core defends itself by shutting down blood flow to the extremities, and on a bike those extremities are in the worst places: hands pushed forward into the wind, feet under the spray and barely moving, ears in the airstream at head height. Most "I was freezing" rides are actually hand-and-foot rides with a warm torso. Two practical rules: protect the extremities one band colder than the chart says if they're what usually hurts you, and start with dry socks and gloves — sweat-damp gloves from the drive to the trailhead lose the battle before the ride starts.

What temperature is too cold to ride a bike?

For the skin, there's a real answer: Environment Canada's frostbite bands. At a 16 mph ride speed:

Risk bands: wind chill of −28 °C (−18 °F) and below, exposed skin can freeze in 10–30 minutes; −40 °C in 5–10; −48 °C in 2–5 (Environment Canada).

Covered skin is a different matter — riders commute through northern winters in the single digits. In practice, ice is the limit before cold is: black ice on shaded corners, freezing spray, and brakes and shifters that stop working when water freezes in the cables. If the roads are dry and every inch of skin is covered, cold alone rarely has to cancel a ride. On hot days the other end of the chart applies, and the job moves to the hydration calculator; a long cold ride still burns carbs, which the fueling calculator plans for.