The Moon isn’t the most hospitable place, but that’s not stopping NASA from sending humans back there soon. Thankfully, an orbiter has now found a region of the Moon with year-round jeans-and-jacket weather – underground caves.

The lunar surface isn’t exactly a prime vacation spot. It’s a pockmarked desert drier than anywhere on Earth, coated in clingy dust that cuts like fiberglass, and exposed to extreme radiation, micrometeorite showers, and wild temperature swings between 127 °C (260 °F) during the day and -173 °C (-280 °F) at night.

A few years ago, NASA’s Lunar Reconnaissance Orbiter (LRO) spotted promising refuge for future lunar explorers – deep pits in the surface that seem to lead down into caves and lava tubes. These could be big enough to hold entire cities, or even Noah’s-Ark-like backups of plant and animal specimens.

These caverns would naturally provide shelter from the radiation and micrometeorite bombardments – and now, new evidence shows they could stabilize the temperature too. NASA scientists used data from Diviner, the thermal camera onboard the LRO, to measure the temperature inside one of these pits, a 100-meter-deep (328-ft) hole in a region known as the Mare Tranquilitatis.

The team found that within the area permanently bathed in shadow, the temperature only changed very slightly over the course of the long lunar day, centering on the comfortable springtime temperature of around 17 °C (63 °F). A person could essentially hang out there wearing just a light jacket.

Of course, any future Moon bases would have pretty careful climate control anyway, but it’s nice to know that perhaps those systems wouldn’t have to work as hard as we thought. The find builds the case for these caves playing a crucial role in humanity’s return to the Moon, which NASA is shooting for as early as 2024.

“Humans evolved living in caves, and to caves we might return when we live on the Moon,” said David Paige, co-author of the study.

The research was published in the journal Geophysical Review Letters.