Cloudy with a chance of...

This global map of Mars was acquired on August 2, 2012, by the Mars Color Imager instrument on NASA's Mars Reconnaissance Orbiter. One global map is generated each day to forecast weather conditions for the entry, descent and landing of NASA's Curiosity rover. The active dust storm observed south of Curiosity's landing site on July 31 has dissipated, leaving behind a dust cloud that will not pose a threat to the landing.

The map is a rectangular projection of Mars (from 90 degrees latitude to minus 90 degrees latitude, and minus 180 degrees longitude to 180 degrees east longitude). The landing site is located on the right side of the map, near 137 degrees east longitude and 4.5 degrees south latitude. The map shows water ice clouds at equatorial latitudes that are typical for late southern winter, when Mars is farther from the sun. Along the southern (bottom) part of the map there are patches of orange clouds, indicating dust lofted into the atmosphere. Small, short-lived dust storms are common at this time of year on Mars and were taken into account when Curiosity's landing system was designed and tested. Larger and more long-lived dust storms are very rare at this time of year.

This global map of Mars was acquired on October 28, 2008, by the Mars Color Imager instrument on NASA's Mars Reconnaissance Orbiter. It was acquired during the same season that NASA's Curiosity rover will land in, but two Mars years earlier. It is remarkably free of water ice clouds when compared with the maps acquired this year in the days leading up to Curiosity's landing.

In 2008, during this season, the planet was dustier than usual. Larger amounts of dust cause sunlight to warm the atmosphere and make it less dense, which means less stopping power for a landing rover. What's more, dusty conditions can lead to an increased chance for small, intense dust storms, another challenge for rover landings. So far, the weather forecast for Curiosity calls for a clearer atmosphere; nonetheless, the spacecraft has been designed to land safely under conditions similar to those observed in 2008.

The map is a rectangular projection of Mars (from 90 degrees latitude to minus 90 degrees latitude, and minus 180 degrees longitude to 180 degrees east longitude). The landing site is located on the right side of the map, near 137 degrees east longitude and 4.5 degrees south latitude. Along the northern (top) and southern (bottom) parts of the map there are patches of orange clouds, indicating dust lofted into the atmosphere.

Map credit 1: NASA/JPL-Caltech/MSSS; map credit 2: NASA/JPL-Caltech/MSSS

Note: NASA has released an additional Martian weather map, that of August 5th, the day Curiosity landed in Gale Crater.