What color temperature range does WELL advocate for during daytime hours?

• A. 2700-3000 Kelvin
• B. 5000-6500 Kelvin
• C. 6500-8000 Kelvin
• D. 4000-4500 Kelvin

Answer: (B)

Light appearance is described by color temperature in Kelvin, with higher numbers meaning cooler, bluer light. For daytime hours, WELL recommends lighting that mimics daylight to help maintain alertness and visual clarity. The best-supported range is about 5000 to 6500 Kelvin, which matches typical daylight and supports a daytime circadian signal. Warmer values like 2700–3000 K feel more like evening light and can reduce alertness; 4000–4500 K is neutral but not as daylight-like; and 6500–8000 K can feel overly cool and potentially harsh. So, the daytime recommendation is 5000–6500 Kelvin.