What to wear in 18 °C
18 °C (64 °F) is the temperature the tool opens on: mild enough for a T-shirt, cool enough that a layer helps. Shuffle for more looks at 18 °C.
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Today’s look
Blush T-shirt, black jeans and white sneakers, with a burgundy leather jacket
Casual, right for 18 °C.
Why this works
- At 18 °C, the burgundy leather jacket handles the time outside and comes off indoors, where the blush T-shirt keeps you comfortable.StandardSchiavon & Lee (2013)
- Blush and burgundy sit next to each other on the colour wheel, so they blend naturally.ResearchSchloss & Palmer (2011)
- The blush T-shirt against the black jeans gives 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 18 °C
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 18 °C (64 °F) that is 0.82 clo. One clo is a unit of clothing insulation.
The outfit. The figure’s garments, with their single-garment values: t-shirt 0.08 + jeans 0.24 + leather jacket 0.40 + sneakers 0.02 + underwear 0.04 + ankle socks 0.02 = 0.80. ISO 9920 turns the sum into the outfit’s insulation: 0.161 + 0.835 × 0.80 = 0.83 clo, right on 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 18 °C
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 |
|---|---|---|---|
| 12 °C (54 °F) | 1.06 | 0.57 | Shirt, jeans and a leather jacket (1.04) |
| 14 °C (57 °F) | 0.99 | 0.55 | Shirt, jeans and a leather jacket (1.04) |
| 16 °C (61 °F) | 0.91 | 0.54 | Shirt, jeans and a leather jacket (1.04) |
| 18 °C (64 °F) | 0.82 | 0.52 | T-shirt, jeans and a denim jacket (0.75) |
| 20 °C (68 °F) | 0.73 | 0.51 | T-shirt, jeans and a denim jacket (0.75) |
| 22 °C (72 °F) | 0.63 | 0.49 | Shirt, jeans and loafers (0.64) |
| 24 °C (75 °F) | 0.52 | 0.48 | T-shirt, chinos and sneakers (0.42) |
A T-shirt and a layer to carry
At 18 °C the outdoor model suggests about 0.82 clo. In practice that is a T-shirt or shirt with trousers, plus a light jacket. The figure’s outfit adds up to 0.83 clo.
Because 18 °C sits between T-shirt weather and jacket weather, personal differences show most here. People who run warm are in short sleeves; people who run cold are in a knit.
Why the numbers are a guide
The outdoor model is a curve fitted to what people in Europe wore outdoors while walking. It fits well, but individuals spread widely around it: its typical error is about 0.16 clo, about the warmth of a polo shirt.
So use the look as a starting point. If you often feel cold at 18 °C, set “runs cold” in the tool and every suggestion gets a little warmer.
Frequently Asked Questions
Is 18 °C warm enough for a T-shirt?
For many people, yes, especially in the sun. Bring a light layer for shade, wind or the evening.
Can I wear shorts at 18 °C?
Yes, if you are comfortable. Many people do on a sunny 18 °C day; others prefer light trousers.
Is 18 °C too cold for a dress?
No. A dress with a light jacket or cardigan is comfortable at 18 °C.
What jacket for 18 degrees?
A light one: denim, a thin bomber, an overshirt or a cardigan.