When we talk about color temperature in regards to LEDs, we're discussing the color of the light an LED provides. For example: Is it amber in color? Is it a bright white? Does it have a blue tint?
Color temperature is measured in Kelvin (K). The lower the color temperature of a light source is, the warmer (redder) the light will be. The higher the color temperature of a light source is, the cooler (bluer) the light will be. Think of the color shift that a piece of metal goes through as it is heated. When you first begin to heat it, the metal has a warm red glow. As the temperature increases, it becomes white-hot, and then finally it becomes a blue color when it is hottest of all.
Candlelight naturally is about 1800K, incandescent bulbs are about 2700K, halogen bulbs are about 3000K, and daylight at noon on a summer's day is about 6500K. LEDs are available in many color temperatures, and when you purchase an LED bulb or fixture, it's important to pay attention to the color temperature to make sure you know what color light it will provide. Note, however, that there is variation within color temperatures, and two bulbs or fixtures may look a little different even if they are the same color temperature on paper.
Which color temperature is right for you and your home? Color preferences are very personal, and so this is a difficult question to answer. Most people tend to prefer LEDs in the 2700K-3000K range because we are used to the color of incandescent and halogen bulbs. Being a bit lower on the Kelvin scale, 2700K has a warm cast to it. It tends to flatter skin tones and warmer color palettes and can make a room feel cozy and comfortable. 3000K, on the other hand, comes across as a more neutral white light. It is more flattering to cooler color palettes, can help a space feel brighter, and helps to keep white surfaces looking white without giving them a yellow cast.
You could, of course, choose LEDs that are higher in color temperature than 3000K - retail and commercial spaces, for example, often utilize color temperatures of 3500K+ for crisp, energetic, neutral white lighting. If you’re able to, the best way to know what color temperature is right for you is to see them in person.
Please note: terms like 'warm white' or 'soft white' can be used differently by different manufacturers, and they can refer to different color temperatures. For example, one manufacturer may use 'warm white' to refer to 2700K, and another may use it to refer to 3000K. The best way to understand the color temperature of an LED is to look at the temperature in degrees Kelvin.