A paper published in Nature Geoscience reveals that data collected at the Gale crater suggests the presence of condensation that appears at night and evaporates during the day.
The soil's composition is key in allowing for such promise as it shows high quantities of perchlorate salts, which would enable water to exist in a liquid form despite the Red Planet's punishing, sub-zero temperatures.
Said the study's lead author, "There have been hypotheses and laboratory studies supporting this possibility before, but this is the first time that we've found evidence that conditions are right for the formation of liquid water on Mars."
However, liquid water likely doesn't stay on the surface for long due to a number of environmental factors.
In addition to it simply freezing, it's particularly prone to vaporizing into a gas as Mars lacks the kind of atmosphere that supports liquid stability.
Evidence found that supports current existence of liquid water on Mars
This image from Curiosity's Mastcam shows inclined beds of sandstone interpreted as the deposits of small deltas fed by rivers flowing down from the Gale Crater rim and building out into a lake where Mount Sharp is now. It was taken March 13, 2014, just north of the "Kimberley" waypoint.
This March 25, 2014, view from the Mastcam on NASA's Curiosity Mars rover looks southward at the Kimberley waypoint. In the foreground, multiple sandstone beds show systematic inclination to the south suggesting progressive build-out of delta sediments in that direction (toward Mount Sharp).
This image shows inclined beds characteristic of delta deposits where a stream entered a lake, but at a higher elevation and farther south than other delta deposits north of Mount Sharp. This suggests multiple episodes of delta growth building southward. It is from Curiosity's Mastcam.
This evenly layered rock photographed by the Mast Camera (Mastcam) on NASA's Curiosity Mars Rover on Aug. 7, 2014, shows a pattern typical of a lake-floor sedimentary deposit not far from where flowing water entered a lake.
This image shows an example of a thin-laminated, evenly stratified rock type that occurs in the "Pahrump Hills" outcrop at the base of Mount Sharp on Mars. The Mastcam on NASA's Curiosity Mars rover acquired this view on Oct. 28, 2014. This type of rock can form under a lake.