Different color temperatures are best for different uses. They can also create the mood of a room. The color temperature of light is measured in Kelvin with a number anywhere from 1000k to 8000k, but you will more typically see numbers from 2700k to 6500k. The lower the number, the warmer, or more yellow, the light will be. The higher the number, the cooler, or more blue, the light will be. Sunlight is typically around 4800k, so any number higher will be a cooler color while a lower number will be a warmer color than sunlight.
Incandescent bulbs usually give off a very warm light, typically close to 3000k. LED bulbs come in so many varieties that you can find them in either warm or cool color temperatures.
One thing to remember is that color temperature has nothing to do with the temperature of the bulb. It only refers to the color of the light output.
Cool light provides more contrast than warm light and so is better suited to tasks such as detailed work. Cool light is best for offices, desks, workshops, or study areas. It creates a focused, energizing environment and helps ease the strain on your eyes.
Warm light is softer and has a more cozy feel. It’s great for dining rooms, living rooms, and bedrooms.
The great thing is that many lamps have a setting that allows you to change the color so you can customize it for the situation. You could have it on cool light for reading in the living room, but then change it to warm light when having guests over.