Dang May

Clouds form when steam rises, which is cold and condenses in the air like droplets. These small particles are relatively dense and light cannot penetrate deep into the cloud before it is reflected out, giving the cloud a distinctive white color. When the clouds get thicker, the droplets can bond to create bigger droplets, then when they're big enough, they fall to the ground like rain.

During the accumulation process, the space between the droplets becomes larger, allowing the light to go deeper into the clouds. If the clouds are large enough, and the droplets are far enough apart, there will be very little light that has entered the cloud to be able to bounce back and forth before they are absorbed. This reflection / absorption process results in a variety of cloud colors, from white to gray and black.

Other colors appear naturally in the clouds. Blue light gray is the result of light scattering in clouds. In the spectrum, blue and green are relatively short wavelengths, while red and yellow are long wavelengths. Short-wave rays are easily scattered by water droplets, and long-wave rays are easily absorbed. Blue light gray is evidence that the scattering produced by droplets of size reaches the level of precipitation in clouds.

Bad colors are observed before extreme weather events occur. The green color of clouds is created when light is scattered by ice. The greenish-colored cumulonimbus clouds are a sign of heavy rain, hail, strong winds and possibly a water cannon.

Cloudy yellow color is rarer, but may occur in the months from late spring to early autumn due to forest fires. The yellow color is probably caused by the presence of smoke.

Red, orange, pink clouds occur mainly at dawn or sunset, and they are the result of light scattering of the atmosphere. Clouds themselves do not have these colors, they only reflect long-wave (non-scattering) rays of light as the main wavelengths during that time. The afternoon before the water cannon in Edmonton, Alberta in 1987, Edmonton residents observed red toward the sun of clouds and dark black on their dark side. In this case, the proverb "red night sky, sailor delight" (red sky at night, sailor's delight) is completely wrong.

According to Wikipedia

Clouds have strange shapes