The average rainfall is 37 inches. The warm climate is characterized both by periods of drought and periods of heavy rain. Prevailing southeasterly winds averaging 12 miles per hour, but which can normally range between 5 and 25 mph, bring salt spray and moisture laden air from the Gulf of Mexico. Hurricanes sometimes inundate the island with saltwater and can cut washover channels from the Gulf to the Laguna Madre in less than a day or two.

Padre Island's location in the northwest corner means that the southeasterly winds prevailing in the Gulf blow many objects, both natural and artificial, onto its shore as well as creating longshore currents which can bring much material for good or bad. Probably the most serious damage to the National Seashore's environment is done by trash, which washes onto the beaches from offshore. The trash comes from a variety of sources including the shrimping industry, offshore natural gas platforms, and washing out of rivers and streams surrounding the Gulf. Much of the trash is either plastic or styrofoam.