Maritime regions—areas near oceans or seas—receive ample moisture from onshore winds, producing moderate temperatures and regular rainfall. Deserts, by contrast, are defined by aridity (very low precipitation) and are usually found far from maritime influence, deep within continents or in rain shadows of mountain ranges.
Coastal deserts (e.g., Atacama, Namib) exist where cold offshore currents suppress rainfall, but they are the exception, not the rule.