Here's why:

* Moonlight is reflected sunlight: The moon itself doesn't emit light, but reflects sunlight that hits its surface.

* Clouds act as mirrors: Clouds are made of water droplets or ice crystals, which are good at reflecting light.

* Reflected light makes clouds visible: When moonlight hits a cloud, some of it is reflected back towards your eyes, making the cloud visible in the darkness.

However, you might not always see clouds at night:

* Cloud thickness matters: Thin clouds are harder to see at night than thick ones, as they reflect less light.

* Moonlight intensity: The brightness of the moon affects how visible clouds are. A full moon will illuminate clouds more effectively than a crescent moon.

* Light pollution: Artificial light can make it difficult to see faint clouds at night.

So, while you might not always be able to see clouds at night, it's definitely possible, thanks to the magic of reflected moonlight!