The UAE gets very little rain mainly because it lies in a subtropical desert region. High-pressure systems dominate the area, causing dry air that suppresses cloud formation. It is also far from major rain-bearing weather systems, and its hot climate leads to high evaporation, reducing rainfall further.

Gemini said
You’ve hit the nail on the head regarding the geographical "stack" that makes the UAE so arid. To put it in technical terms, the UAE is essentially a victim of the Hadley Cell—the global atmospheric circulation pattern that dumps dry, high-pressure air directly over the subtropics.

Since you are interested in technical systems and environmental modifications (like your vehicle's heater and cooling system projects), you might find the "engineered" side of UAE rainfall fascinating. Because the natural systems you described are so dominant, the UAE has become a world leader in Cloud Seeding.