Warm lighting feels more natural for us in the evenings. As part of our natural human circadian rhythm, the warm light seems to relax us and help us wind down for the say, get ready for sleep. While cool lighting helps us be alert and energetic for performing tasks, cool lighting in our evening spaces may interfere with our inner clock. We think of reddish light as warmer and bluish light as cooler. Warmer light promotes relaxation.