According to Space.com, the atmosphere on Mars is around 100 times thinner compared to that of the Earth's and is composed of about 95 percent carbon dioxide. However, the Martian atmosphere is still thick enough to sustain weather, winds and clouds.
Space.com explains that aside from carbon dioxide, the atmosphere of Mars is also composed of 2.7 percent nitrogen, 1.6 percent argon, 0.13 percent oxygen, 0.8 percent carbon monoxide and small amounts of nitrogen oxide, krypton, hydrogen-deuterium-oxygen, neon, xenon and water. Dust storms formed in Mars last for months and are the biggest in the solar system. Moreover, the snowflakes on this planet are composed of carbon dioxide instead of water and are said to be similar in size with red blood cells.