A top priority in our exploration of Mars is understanding its present climate, what its climate was like in the distant past, and the causes of climate change over time.

What's the Martian Climate Like Today?

The current Martian climate is regulated by seasonal changes of the carbon dioxide ice caps, the movement of large amounts of dust by the atmosphere and the exchange of water vapor between the surface and the atmosphere. One of the most dynamic weather patterns on Mars is the generation of dust storms that generally occur in the southern spring and summer. These storms can grow to encompass the whole planet. Understanding how these storms develop and grow is one goal of future climatic studies.

A better understanding of Mars' current climate will help scientists more effectively model its past climatic behavior. To do that, we'll need detailed weather maps of the planet and information about how much dust and water vapor are in the atmosphere.

Monitoring the planet for this information over one full Martian year (687 Earth days) will help us understand how Mars behaves over its seasonal cycle and guide us toward understanding how the planet changes over millions of years.

The layered terrain of the Martian polar regions also holds clues about the planet's past, much like the rings of a tree provide a record of its history. When and how were these polar layers deposited? Was the climate of Mars ever like that of Earth? And if so, what happened to change the planet into the dry, cold, barren desert it is today? Those are the questions that our missions still have to answer.