Temperature Measurements Taken by Phoenix Spacecraft
Jet Propulsion Laboratory https://www.jpl.nasa.gov/ Sept. 30, 2008
This chart plots the minimum daily atmospheric temperature measured by NASA's Phoenix Mars Lander spacecraft since landing on Mars. As the temperature increased through the summer season, the atmospheric humidity also increased. Clouds, ground fog, and frost were observed each night after the temperature started dropping.
Photojournal Note: As planned, the Phoenix lander, which landed May 25, 2008 23:53 UTC, ended communications in November 2008, about six months after landing, when its solar panels ceased operating in the dark Martian winter.