What to Wear Running in 40°F Weather
40°F is 4°C. Everything below applies to either reading — the kit does not care which scale you think in.
Properly cold. Insulate the core, protect hands and ears, and block the wind.
What to Wear
Running kit for 40°F
- ●Base layer or thermal top
- ●running tights
- ●gloves
- ●ear band
What 40°F actually feels like once you are moving
40°F is not what your skin gets. Running at 6 mph makes 6 mph of headwind out of still air, bringing 40°F down to around 36°F on exposed skin — roughly 4 degrees. That is real, but it is a fraction of the penalty a cyclist pays in the same air, and you are producing far more heat than a walker to set against it. At 40°F a runner is usually the best-off of the three: cold for the first few minutes, then comfortably warm.
Dress for the finish, not the doorstep
Your own engine is worth about 18°F once you are going. The practical rule is to dress for 58°F standing still rather than the 40°F on the forecast. Running gets the largest correction of the three because it makes the most heat, and runners still under-apply it. If you are comfortable on the doorstep at 40°F you are dressed for a walk, and you will be carrying a soaked layer by the second mile.
Not sure of the temperature? Enter your city in the free tool for live conditions, a Ride Score, and rain- and wind-adjusted advice.
Open the live toolThe first ten minutes
Aim to be a little cold for the first five to ten minutes. At 40°F that discomfort lifts almost exactly as your output rises, and it is the most reliable sign the layers are right. If it has not passed by the second mile, add one next time.
What changes at 40°F when it is wet, windy or bright
Rain
Rain at 40°F runs like roughly 25°F dry, but it troubles a runner less than it troubles anyone else here: you are making enough heat to stay ahead of it, and you are out for less time than a walker. A light shell helps; a heavy one will have you wetter from the inside than the rain would have made you.
Wind
A 15 mph headwind at 40°F adds meaningfully to the 6 mph you make yourself, and it lands hardest on an out-and-back — the half you run into it will feel colder and slower than the half with it behind. A thin windproof front is the right answer; run out into the wind and back with it where the route lets you choose.
Sun
Bright low sun at 40°F feels several degrees warmer than it is, and drops straight back the moment you turn into shade. Dress for the shaded stretches and for the last hour, not for the doorstep in full sun.
The mistake people make at 40°F
40°F is the most over-dressed temperature in running. It sounds cold, so people reach for winter kit, finish soaked, and only then get properly cold walking back from the door. Cover the arms, keep the wind off the chest, and leave the legs alone unless it is wet.
Hands, feet and ears
40°F is the range where a runner wants light gloves for the first mile and then wants rid of them — which is the argument for the cheap thin pair you do not mind stuffing into your waist or a vest pocket. Ears matter more than hands once the wind is up.
Frequently asked
What should I wear running in 40°F?
For 40°F, wear: Base layer or thermal top, running tights, gloves, ear band. Dress for about 58°F rather than 40°F, because your own effort is worth roughly 18 degrees once you are moving.
Does 40°F feel colder when you are running?
Yes. At 6 mph you generate 6 mph of headwind out of still air, which brings 40°F down to around 36°F against exposed skin before any real wind is counted.
Should I dress differently running at 40°F than for cycling or walking?
Yes. A runner makes about three times a walker's heat, so you need noticeably less at 40°F than a walker does — but you make only 6 mph of airflow against a cyclist's 16, so you need less wind protection than a rider. Running is the least-clothed of the three at almost any temperature.
Is 40°F too cold to go running?
No, as long as you dress for it and keep the exposure sensible. At 40°F, insulate the core, block the wind, and cover hands, ears and face; the limiting factor is usually something that leaves you standing still, not the running itself.
Do I need a jacket at 40°F?
Yes — at 40°F you want a layer that both insulates and blocks the wind, over a dry layer that moves sweat away from the skin.
What should I wear running in 4°C?
4°C is 40°F, so the answer on this page is the one you want: Base layer or thermal top, running tights, gloves, ear band. Nothing about the advice changes with the scale — only the number you read off the forecast.
What changes if it rains at 40°F?
Treat it as roughly 25°F. Add a windproof or water-resistant shell over the same kit rather than adding insulation underneath — wet insulation holds water against the skin and is worse than none.