Buses Making Rainbows in China: The Real Purpose and Where to Spot Them


In recent years, you may have heard about a fascinating and colorful phenomenon occurring in various parts of China: buses making rainbows. While this may seem like a magical spectacle, there’s a scientific explanation behind it, as well as a purpose that goes beyond just visual appeal. In this article, we will explore why buses in China create rainbows, the real purpose behind this phenomenon, and where you can spot these vibrant displays of color.

The Science Behind Buses Making Rainbows

The phenomenon of buses creating rainbows primarily stems from the use of special prismatic films or coatings on their windows. These films are designed to reflect and refract sunlight in a way that produces a stunning display of colors. When sunlight passes through or reflects off these films, it gets separated into its various constituent colors, creating the rainbow effect.

Reflective Films

Some buses in China are equipped with window films that have a high degree of reflectivity, particularly in the infrared spectrum. These films serve a dual purpose: they help regulate the internal temperature of the bus by reflecting a significant portion of the sun’s heat and UV radiation, and they create the rainbow effect when sunlight strikes them at the right angle.

Prismatic Coatings

Another technique involves applying prismatic coatings to bus windows. These coatings contain microscopic structures that diffract sunlight, causing it to spread into its component colors. As the angle of sunlight changes throughout the day, the rainbow effect can vary in intensity and position.

The Real Purpose: Energy Efficiency and Comfort

While the rainbow effect on buses is undeniably captivating, its primary purpose is to enhance energy efficiency and passenger comfort. China experiences hot summers, and buses can become uncomfortably hot due to the greenhouse effect caused by sunlight passing through the windows. The reflective films and prismatic coatings help reduce the amount of heat and UV radiation entering the bus, making the interior cooler and more comfortable for passengers. This, in turn, reduces the need for energy-intensive air conditioning and benefits both the environment and the economy.

Where and When to Spot the Rainbow

The rainbow effect on buses is most prominent when sunlight strikes the windows at specific angles. Typically, you can spot these rainbows:

  1. During Sunny Days: Obviously, sunny days are the best time to witness the rainbow effect. Sunlight is essential for creating the dazzling display of colors.
  2. Morning and Evening: The angles of sunlight are often ideal during the early morning and late afternoon hours. This is when the sun is lower on the horizon, allowing sunlight to interact with the bus windows at a more oblique angle, producing more pronounced rainbows.
  3. When the Bus is Stationary: The rainbow effect is most noticeable when the bus is stationary or moving slowly, as this gives observers more time to appreciate the beautiful colors.


Buses making rainbows in China are a delightful fusion of science, technology, and practicality. Beyond their aesthetic appeal, the shimmering rainbow effect serves to enhance energy efficiency and passenger comfort, especially during hot summer days. So, if you find yourself in China on a sunny day, be sure to keep an eye out for these colorful buses, and don’t forget to appreciate the science and innovation behind their shimmering rainbows.

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