Why do rainfall amounts decrease farther inland in Libya?

Rainfall amounts decrease farther inland in Libya primarily because the country's climate is dominated by the hot, arid Sahara, which exerts a stronger influence away from the coast.1

While the northern coastal regions are moderated by the Mediterranean Sea and receive moisture from prevailing westerly winds that bring cyclonic storms between October and March, these effects diminish as one moves inland. The coastal Mediterranean climate transitions into a narrow band of semiarid steppe and eventually into the extreme aridity of the Saharan interior.1

This inland decline in precipitation is further exacerbated by the ghibli, a hot, arid wind that blows from the south, carrying sand and causing a rapid drop in relative humidity. Consequently, while coastal cities like Tripoli receive significantly more annual rainfall, inland areas such as Sabhā experience extreme aridity, often receiving less than one inch of precipitation annually.1