“What’s this planet that I never expected you to visit like? Uh… It’s a desert planet. It’s covered in desert. It’s hot and dry and sandy. All over.”
The problem is less one of lack of realism and more that you start training your players to be overly genre savvy and expect all the planets to be like this.
Which of course makes this a trick ripe for subversion. Train your players to think all planets are single-biome planets, and then just when they’re comfortable throw them a major curveball. A planet which has multiple terrain types, in a majorly plot-relevant way that is actively dangerous if they assume otherwise. (Details left as an exercise for the reader. We’re sure you’re smart enough to think of something.)