Plant life is abundant at Fort Matanzas. This is primarily because the park receives an average of 49 inches of rain per year, and maintains an average annual temperature of 70 degrees Fahrenheit. Hard freezes are uncommon, which means the growing season extends throughout most of the year. Additionally, the park is located on portions of two barrier islands. Barrier islands, when left undeveloped, are comprised of several different plant communities spanning a relatively constricted geographical range. At Fort Matanzas these communities are represented by primary and secondary sand dunes, coastal scrub, maritime hammock, and estuarine salt marsh. This ecological diversity, and the plant-friendly sub-tropical climate, account for why over 250 individual plant species have been identified so far at Fort Matanzas, a park totaling only 300 acres in size.