One Side of the Moon is Much Hotter Than the Other

One Side of the Moon is Much Hotter Than the Other

The Science Behind the Moon’s Extreme Temperatures

When you look up at the Moon, it seems like a calm, cold, and constant companion in the sky. But beyond its peaceful glow lies a startling truth: temperatures on the Moon vary wildly, and one side can be significantly hotter than the other. In fact, the surface of the Moon can go from boiling hot to freezing cold, depending on which side faces the Sun.

This dramatic difference in temperature isn’t just interesting trivia—it’s a real challenge for scientists, space agencies, and future lunar explorers. So, why is one side of the Moon much hotter than the other? The answer lies in the Moon’s rotation, sunlight exposure, and lack of atmosphere.

The Moon's Strange Day-Night Cycle

To understand the Moon’s temperature differences, we first need to understand its rotation.

Unlike Earth, which completes a full day every 24 hours, the Moon takes about 27.3 Earth days to rotate once on its axis. But because of its orbit around Earth, a full lunar "day"—from sunrise to sunrise—actually lasts about 29.5 Earth days.

This means any given spot on the Moon experiences two weeks of continuous sunlight, followed by two weeks of complete darkness.

That’s right—on the Moon, "daytime" lasts 14 Earth days, and "nighttime" lasts another 14. As a result, the side of the Moon facing the Sun during those two weeks becomes extremely hot, while the side in darkness becomes extremely cold.

Tidal Locking and the Two Faces of the Moon

The Moon is tidally locked with Earth. That means it always shows the same face—the near side—to us. The far side, often called the "dark side" of the Moon (though it gets just as much sunlight), always faces away.

However, the temperature extremes are not caused by which side is facing Earth. Instead, they depend entirely on which side is facing the Sun during that two-week period.

Still, there are some long-term average differences between the near and far sides. This is due to the Moon’s composition and surface features.

Surface Differences: Why the Near Side Warms Up More

If you compare the two sides of the Moon, they’re surprisingly different.

The near side has large, dark plains known as maria—basaltic lava fields that formed from ancient volcanic activity. These darker surfaces absorb more sunlight and heat up more quickly.

The far side is covered in lighter-colored highlands, which reflect more sunlight and don’t heat up as fast.


This means the near side can be slightly hotter on average during the lunar day, simply because it absorbs more solar energy. Over time, this adds to the perceived difference between the two sides.

The Role of Atmosphere—Or Lack of It

Here on Earth, our atmosphere acts like a protective blanket. It helps:

Distribute heat between the day and night sides

Trap warmth during the night

Protect us from the Sun’s radiation


The Moon, however, has no significant atmosphere. That means it cannot hold heat once the Sun goes down, and it has no way to regulate surface temperature. As a result:

Lunar daytime temperatures can soar to 127°C (260°F)

Lunar nighttime temperatures can drop to -173°C (-280°F)


This makes the Moon one of the most extreme environments in our solar system.

Why This Matters for Lunar Missions

These temperature swings aren’t just academic—they have real-world impacts on space missions.

Satellites, rovers, landers, and future Moon bases need to survive both the scorching lunar day and the freezing lunar night. That requires:

Special materials that can withstand high and low temperatures

Thermal insulation systems

Energy sources (like solar panels and batteries) that can work through the dark, cold weeks


This is one reason many space agencies, including NASA’s Artemis program, are targeting the Moon’s poles for exploration. In these regions, some areas receive nearly constant sunlight, while others—especially within deep craters—may contain permanently shadowed ice.

These polar regions offer a more stable temperature range and access to potential water sources—two key factors for building sustainable lunar habitats.

Final Thoughts: A Harsh, Beautiful Neighbor

The Moon may appear still and quiet, but it’s a world of extremes. With two-week-long days and nights, no air to hold warmth, and huge differences in terrain, the lunar surface challenges every assumption we have about planetary life.

While no side of the Moon is always hot or cold, whichever side faces the Sun becomes blistering hot, and the side in darkness turns deathly cold. On average, due to surface composition, the near side does tend to absorb more heat—but both sides are equally extreme depending on the time of the lunar cycle.

As we prepare to return to the Moon, these details are more important than ever. Every mission must be carefully planned, every structure thoughtfully engineered, to survive in one of the most extreme environments we've ever attempted to call home.

So next time you look up at the Moon, remember—beneath its calm glow lies a harsh, complex world, full of secrets still waiting to be uncovered.