Quick answer: dress as if it were 5 to 10 degrees warmer than what the thermometer says. If you feel a little cold when you step out the door, you’re doing it right. Use thin layers of technical fabric, never cotton, and protect your hands, ears, and neck before the rest of your body.
The first few cold days always catch someone off guard. Either you go out with three layers and ten minutes later you're running with your jacket tied around your waist, or you head out in short sleeves because "you'll warm up eventually" and you never do. Both things happen to everyone. Both have easy solutions.
The 10-degree rule
When you run, your body generates a lot of heat. That's why your actual sensation after ten minutes is quite a bit warmer than the street temperature.
The rule of thumb: add 5 to 10 degrees to the outdoor temperature and dress for that figure.
- Easy run: add about 5 degrees. You're going slower and generating less heat.
- Intervals or high pace: add up to 10. You're going to sweat, and trapped sweat is what chills you later.
If you're going out for intervals at 4 °C, dress as if it were 14 °C. You won't be comfortable for the first five minutes. That’s normal.
What to wear based on the temperature
A guideline to get started. Then, each person adjusts according to how they handle the cold.
| Temperature | Top | Bottom | Extras |
|---|---|---|---|
| Above 15 °C | Singlet or short sleeves | Shorts | — |
| 10–15 °C | Short sleeves or singlet. Thin long sleeves if it's windy | Shorts | — |
| 5–10 °C | Technical long sleeves. Thin windbreaker if it's breezy | Shorts or tights | Thin gloves if you get cold easily |
| 0–5 °C | Long-sleeve base layer + windbreaker or vest | Long tights | Thin gloves, ear warmer headband |
| Below 0 °C | Base layer + mid-layer + windbreaker | Thermal tights | Gloves, beanie, neck gaiter |
The three-layer system, simplified
You don't always need to wear three. You just need to understand what each one is for:
- Base layer. It sits against your skin and its job is to wick sweat away. If this fails, nothing else matters: a wet base layer will chill you even if you're wearing a good jacket over it.
- Mid-layer. Retains heat. Only necessary below 0 °C or if you feel the cold very easily.
- Outer layer. Protects you from wind and rain. It should be thin and allow vapor to escape. A regular rain jacket will turn you into a sauna.
With two well-chosen layers, you can run through almost the entire winter in most of Spain.
Wind counts for more than degrees
Here in Zaragoza, we know this well: 8 °C without wind is a pleasant day, but 8 °C with the "cierzo" wind is a different story. The wind strips away the heat your body generates, and the "feels like" temperature can drop by several degrees.
Three things that work:
- If it's windy, a thin windbreaker is worth more than an extra insulating layer.
- Start against the wind and head back with it. At the end, when you're tired and sweaty, the last thing you want is the wind in your face.
- Protect your neck. A thin neck gaiter makes a big difference and fits in a pocket when you don't need it.
Hands, ears, and neck first
When it's cold, the body protects the core and sends less blood to the extremities. That's why your hands and ears are the first to freeze, even if the rest of you is fine.
Thin gloves and an ear warmer headband weigh almost nothing and allow you to dress lighter elsewhere. If you get too warm, just pocket them.
On your legs, however, it's rarely necessary. They move the whole time and generate a lot of heat. Many people run in shorts down to 5 °C without any issues.
The mistakes that make you coldest
- Cotton. It absorbs sweat, doesn't release it, and stays cold and heavy against your skin. It's the number one mistake.
- Overdressing. You sweat a lot in the first half and you're soaked in the second. You feel much colder when wet than with less clothing.
- Stopping when you finish. As soon as you stop, the sweat cools you down very quickly. Have something dry to change into, or finish close to home.
- Warming up outside slowly. If you can, do your mobility work inside and go out ready to run.
How I apply this
Before your next cold-weather run:
- Check the temperature and the wind.
- Add 5 degrees if it's an easy run, 10 if it's a hard session.
- Choose from the table for that number.
- Add thin gloves and a headband if it's below 5 °C.
- Start out feeling a little cold. If you're still cold ten minutes in, make a note of what you were missing for next time.
After two or three runs, you’ll have your own table, which is the only one that truly matters.
About what we wear
Our primary garment is a racing singlet: 69 grams, seamless, and with a perforated panel. It is not a winter garment, and we won't tell you otherwise. But the principle is the same as in this guide: less weight, nothing that chafes, and a fabric that lets heat escape. It is the garment for race days, when the cold stays at the starting line.
Frequently asked questions
Is it bad to run in the cold?
No, as long as you're dressed properly and warm up well. We'll cover this in more detail in a future article.
What should I wear to run at 0 degrees?
A long-sleeve base layer, windbreaker or vest, long tights, thin gloves, and something for your ears. If it's windy, add a neck gaiter.
Tights or shorts in winter?
Shorts down to about 5 °C for most. Below that, or if it's very windy, long tights.
How do I know if I'm overdressed?
If you're comfortable when you step out, you're overdressed. Ten minutes in, you should feel good, without excessive sweating.
Run in the cold, but don't be cold. A little better tomorrow than today.
— Daniel Serrano, EKATÒ™ Journal