What to wear in 40 °F weather
At 40 °F (4.4 °C) most people want a proper winter layer. The figure is dressed for a dry 40 °F day; shuffle for another look at the same warmth, or set your own weather.
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Today’s look
Cream tank top, tan cargo trousers and cream sneakers, with a sage cardigan and a charcoal puffer jacket
Casual, right for 40 °F.
Why this works
- The sage cardigan is the one colour; everything else is calm, so it stands out without competing.Less sure · ConventionSchloss & Palmer (2011)
- At 40 °F, the charcoal puffer jacket handles the time outside and comes off indoors, where the sage cardigan keeps you comfortable.StandardSchiavon & Lee (2013)
- The tan cargo trousers against the charcoal puffer jacket give a clear light-and-dark contrast, which people tend to like.ResearchSchloss & Palmer (2011)
Or try
Wearing this today?
Log it, and the picks rotate what you wear.
How this works: Method, 7 sources,
How this works
Method
With no wardrobe it builds a look from colour schemes; with yours it picks from what you own, leaving out pieces archived, in the wash or worn recently. A pick must suit the occasion and the weather, then it is scored on colour harmony (the Ou–Luo model and scheme rules, in OKLab), light against dark, warmth (garment insulation summed as in ISO 9920, against the UTCI clothing model), formality and rotation. The same day and wardrobe give the same pick until you shuffle.
Sources
- Ou, L.-C. & Luo, M. R., "A colour harmony model for two-colour combinations", Color Research & Application 31(3) (2006)
- Schloss, K. B. & Palmer, S. E., "Aesthetic response to color combinations", Attention, Perception & Psychophysics 73(2) (2011)
- Ottosson, B., "A perceptual color space for image processing" (OKLab) (2020)
- ISO 9920, Ergonomics of the thermal environment: estimation of thermal insulation of a clothing ensemble
- ANSI/ASHRAE Standard 55, Thermal Environmental Conditions for Human Occupancy (garment insulation table)
- Havenith, G. et al., "The UTCI-clothing model", International Journal of Biometeorology 56(3) (2012)
- MET Norway, Locationforecast 2.0 (weather data, CC BY 4.0)
Changes
- Added 21 pages: what colours go with navy, black, grey, beige, olive, burgundy, brown, white, denim and pink (each table from the engine), and what to wear from 40 to 80 °F and 5 to 25 °C.
- First published.
How warm the figure’s outfit is at 40 °F
The target. The UTCI clothing model gives the insulation people typically wear outdoors at an air temperature T in °C: 1.372 − 0.01866·T − 0.0004849·T² − 0.000009333·T³. At 40 °F (4.4 °C) that is 1.28 clo. One clo is a unit of clothing insulation.
The outfit. The figure’s garments, with their single-garment values: tank top 0.06 + cardigan 0.25 + cargo trousers 0.24 + puffer jacket 0.60 + sneakers 0.02 + beanie 0.05 + scarf 0.05 + underwear 0.04 + ankle socks 0.02 = 1.33. ISO 9920 turns the sum into the outfit’s insulation: 0.161 + 0.835 × 1.33 = 1.27 clo, 0.01 below the target.
The tool counts an outfit as right for the weather when it is within about a third of a clo below or four tenths above the target. Values for coats and jackets are estimates; the rest come from the ASHRAE 55 garment table.
How much to wear around 40 °F
Clothing insulation in clo: outdoors from the UTCI clothing model, indoors from the office model (Schiavon & Lee), with a typical outfit near the outdoor figure.
| Temperature | Outdoors | Indoors | About this warm |
|---|---|---|---|
| 25 °F (-4 °C) | 1.44 | 0.96 | Shirt, sweater, trousers and a wool coat (1.51) |
| 30 °F (-1 °C) | 1.39 | 0.86 | Shirt, sweater, trousers and a wool coat (1.51) |
| 35 °F (2 °C) | 1.34 | 0.76 | Long-sleeve tee, sweater, jeans and a trench coat (1.19) |
| 40 °F (4 °C) | 1.28 | 0.66 | Long-sleeve tee, sweater, jeans and a trench coat (1.19) |
| 45 °F (7 °C) | 1.21 | 0.61 | Long-sleeve tee, sweater, jeans and a trench coat (1.19) |
| 50 °F (10 °C) | 1.13 | 0.59 | Long-sleeve tee, sweater, jeans and a trench coat (1.19) |
| 55 °F (13 °C) | 1.03 | 0.57 | Shirt, jeans and a leather jacket (1.04) |
Coat weather, with a knit underneath
The outdoor clothing model behind this page says people wear about 1.28 clo at 40 °F, roughly a sweater and trousers under a padded or wool coat. A clo is a unit of insulation; a business suit is about one. The look above comes to 1.27 clo.
Indoors you will want much less, which is why the outfit is built in layers: a base you are comfortable in at your desk, and a coat that comes off at the door.
Hats, scarves and gloves earn their place now
A scarf or beanie adds little to the body’s overall insulation (a few hundredths of a clo each in the tool’s estimates), but heads, necks and hands lose heat fast and feel the cold first, so at 40 °F they make a bigger difference to comfort than the numbers suggest.
Wind makes 40 °F feel much colder, because moving air cuts through clothing. If you turn on the forecast, the tool dresses for the “feels like” temperature instead of the air temperature.
Frequently Asked Questions
Is 40 degrees cold enough for a winter coat?
For most people, yes. The clothing model behind this page puts typical outdoor clothing at 40 °F close to a sweater under a warm coat. If you run warm or are walking briskly, a lighter jacket over a thick knit can be enough.
Can I wear shorts in 40 °F weather?
Some people do for a short run, because exercise makes heat. For standing or walking, bare legs at 40 °F lose heat quickly; trousers, or tights under a skirt, are the comfortable choice.
Do I need gloves at 40 °F?
Not always, but hands get cold fast at this temperature, especially in wind or when holding a phone. Light gloves or pockets make a long walk more pleasant.
What shoes should I wear at 40 °F?
Closed shoes or boots with socks. Boots add a little warmth and keep out rain and slush; leave sandals and canvas for warmer days.