Sunny days on Mars come with a weather warning: Dust storms ahead!

The Hubble Space Telescope captured this crystal-clear view of Mars and its two moons Phobos and Deimos in mid-July, when a massive dust storm was still raging across the planet's surface. Today, the Red Planet will reach opposition, when it is on the opposite side of Earth as the sun. Mars will make its closest approach to Earth since 2003 on Tuesday (July 31). .

The weather report from Mars may soon come with a forecast for dust storms, following the discovery that, in 78% of cases, a Red Planet dust storm is preceded by an unusually high amount of solar heating.

Dust storms are one of Mars' natural wonders, and also one of its greatest hazards. They begin on small scales, but some can blow up into global storms that enshroud the Red Planet in obscuring dust, hiding even the largest surface features from our prying eyes.