why do deserts have sand dunes

Basically, the main difference comes down to temperature and location rather than just the lack of rain. When I'm out moving around the globe, I've seen plenty of both. Hot deserts are what most people think of, like the Sahara, where the sun just beats down on you all day and the sand is like a furnace. They're usually found near the equator where the air is dry and the heat is intense enough to make you feel like you're baking.

On the flip side, cold deserts are a totally different story. Think of places like Antarctica or parts of Central Asia. Even though they don't get much precipitation, it's freezing cold most of the time. Instead of sand, you're looking at ice, snow, or rocky ground that stays permafrost. It's wild because even though it's technically a desert because of the moisture levels, you'd never want to walk around there without some serious gear.