Is it really colder at the top of Jebel Jais?

The altitude makes a huge difference. At nearly 2,000 meters, the air is thinner and cooler. In the peak of summer when Dubai is 45°C, the summit might be a manageable 30°C with a stiff breeze. In winter (December-February), daytime temperatures can be 10-15°C, and nights get very cold—sometimes approaching freezing. We strongly recommend bringing a light jacket or sweater regardless of when you visit, as the wind can make it feel cooler than the thermometer reads.