A colour with a red, orange or yellow bias — associated with heat, sunlight and cosiness.
In Colourwise's classification, a colour whose OKLCH hue falls roughly between 20° and 95°.
Warm/cool is a design convention, not a measured physical property of light temperature.
Terracotta and mustard are warm colours.
Warm colours are commonly recommended for north-facing rooms to counteract cool daylight.
Warmth is a classification, not a measurement. Colourwise assigns it from the OKLCH hue angle, treating 20° to 95° as warm, and only once HSV saturation reaches 8% so that a hue angle means something. Other systems draw the line elsewhere, and painters use the word relatively: one red is 'warmer' than another when it leans towards orange and 'cooler' when it leans towards blue.
| Colour | OKLCH hue | Colourwise undertone |
|---|---|---|
| Terracotta #e2725b | 32.9° | Warm |
| Ochre #cc7722 | 59.6° | Warm |
| Mustard #ffdb58 | 93.7° | Warm |
| Gold #ffd700 | 95.3° | Neutral band |
| Lemon Yellow #fff44f | 105.5° | Neutral band |
Mustard, at 93.7°, is the last of these inside the warm arc. Gold at 95.3° and Lemon yellow at 105.5° fall in the band Colourwise leaves unassigned, because a yellow that leans towards green stops reading as warm to most people even though it is still yellow.
How this was calculated: OKLCH hue angle of each catalogue HEX value, set against the 20° to 95° arc the classifier treats as warm.
A warm paint colour is chosen for a north-facing room to offset its cool daylight.
The advice works best for mid-strength colours. A very pale warm white has so little chroma that cool daylight can cancel it and leave a flat grey. Test a large sample on the darkest wall before buying.