UAE Rainfall Patterns: Eastern Coastal Plain Wetter Than Western Due to Monsoon Winds and Mountain Rain Shadow

The eastern coastal plain (Fujairah, Kalba, Khor Fakkan, Dibba) receives ~100–150 mm/year—double the western plain (Abu Dhabi, Dubai, Sharjah, Ajman, Umm Al Quwain) at ~50–80 mm/year.

Why?

1. Orographic lift: Hajar Mountains (700–1,900 m) run parallel to east coast. Moisture-laden southeasterly monsoon winds (June–Sept) from Indian Ocean hit slopes, rise, cool, condense → rain on eastern slopes/coastal plain.
2. Rain shadow: Western side of Hajars (inland/western plain) receives descending, dry air — minimal rain.
3. Winter fronts: Both coasts get some rain from mid-latitude systems (Dec–Mar), but east still favored.

Other Factors

• Sea breezes: Daytime onshore flow enhances convection east.
• Urban heat island: Dubai/Abu Dhabi may slightly enhance convection but lack moisture.
• Cloud seeding: UAE conducts operations; targets eastern mountains primarily.

Result: Eastern UAE is greener (wadi farms, date palms, mangroves); western UAE is hyper-arid, dependent on desalination.