The sun shines on the desert during the day. The sunshine warms up the sand. Because the sand gets warm, the desert feels very hot!
When the sun goes down and night comes, there is no sunshine to keep the sand warm. So, the sand cools down quickly. That makes the desert cold at night.
In short:
- Daytime: Sun warms the sand → Desert is hot.
- Nighttime: No sun, sand cools → Desert is cold.
Caption: The sun warms the desert sand during the day, making it hot. At night, the sand cools quickly because there is no sun, so the desert becomes cold.