Closest to the Sun, but not the hottest. Boiling by day, freezing by night.
Mercury has almost no atmosphere to hold onto warmth. Facing the Sun, the rock boils at 430°C. But the moment night falls, all that heat radiates straight into the vacuum of space, plunging the dark side to -180°C.
Mercury has a solid rocky ground, so a probe can touch down. However, with virtually no atmosphere, standing without a heavy pressurized suit would cause your blood to boil immediately. In sunlight, the ground bakes at 430°C (hot enough to melt zinc); step into shadow, and you instantly freeze at -180°C while cosmic rays bombard the soil.
Verified science answered in plain, accessible language.
Because Mercury has virtually no atmosphere (only an ultra-thin exosphere), it cannot retain heat. Day temperatures reach 430°C (806°F) while night temperatures plunge to -180°C (-292°F).
No. Despite being closest to the Sun, Venus is hotter than Mercury because Venus has a runaway greenhouse atmosphere trapping immense heat.
Yes! Radar observations and NASA's MESSENGER probe confirmed water ice inside permanently shadowed craters at Mercury's poles.
The estimated average temperature on Mercury is +167°C / +332.6°F.
A full day-night cycle on Mercury lasts about 4222.6 Earth hours.
Mercury is 77 – 222 million km from Earth.
Mercury's atmospheric pressure is < 10^-14 bar (Ultra-high vacuum exosphere).
Virtually none — an ultra-thin trace of sodium, potassium, and oxygen that cannot trap warmth.
Zero wind. Without an atmosphere, there is complete silence.
None. No air means no clouds, no rain, and no weather systems.
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