Brownsville, Texas - Geography and Climate

Geography and Climate

Brownsville is located on the U.S.-Mexico border (marked here by the Rio Grande or Río Bravo del Norte) from Matamoros, Tamaulipas.

Broadleaf evergreen plants, including palms, dominate Brownsville neighborhoods to a greater degree than is seen elsewhere in Texas—even in nearby cities such as Harlingen and San Benito. Soils are mostly of clay to silty clay loam texture, moderately alkaline (pH 8.2) to strongly alkaline (pH8.5) and with a significant degree of salinity in many places.

According to the city of Brownsville, the city has a total area of 147.5 square miles (382 km2), making it by far the largest American city by land area in the lower Rio Grande Valley and third largest American city by land area along the U.S.-Mexico border, after San Diego, California and El Paso, Texas. 144.9 square miles (375 km2) of it is land and 2.6 square miles (6.7 km2) of it (3.16%) is water.

In addition to being the southernmost city in Texas, Brownsville is among the southernmost of all U.S. cities. Only Hawaiʻi and a handful of municipalities in Miami-Dade and Monroe counties (plus tiny Everglades City in Collier County) in Florida are at a more southerly latitude than Brownsville, which lies at roughly the same latitude as North Miami Beach in northern Miami-Dade County; thus, Brownsville is farther south than such well-known, tropical Florida cities as West Palm Beach, Ft. Myers, and Fort Lauderdale.

Brownsville is now one of the first cities in the U.S. and Texas to ban the use of plastic shopping bags, reaching closer toward its goals of a greener, cleaner city. This has led other cities in the area to also consider such a ban. In addition, Forbes has identified Brownsville as one of 12 metro areas in the U.S. with the cleanest air; Laredo, Texas was the only other Texas metro area to be among the 12.

Brownsville received the theoretical maximum worst score (72) for its level of human influence on the environment. This is the place where the maximum was observed. It ranked higher than the most populous metropolitan cities.

Brownsville has a humid subtropical climate (Köppen Cfa), just outside of a hot semi-arid climate. Yet the nearby ocean waters of the Gulf of Mexico help keep Brownsville cooler during the summer relative to cities further inland such as Laredo and McAllen. Thus temperatures above 100 °F (37.8 °C) are uncommon, with an average of only 1.1 days reaching that level of heat. At the other extreme, there is an average of one to two nights per year with freezing temperatures. Rainfall tends to be the heaviest in summer and early part of fall, although it is not unheard of for Brownsville to go for weeks or sometimes months without any rainfall even during the "wet" season. Extreme temperatures range from 12 °F (−11 °C) in February 1899 to 106 °F (41 °C) in March 1984. The greatest snowfall in a day and a season was 1.5 inches (3.8 cm), which fell on December 25, 2004.

Brownsville's location at the intersection of different climate regimes (subtropical, Chihuahuan desert, Gulf Coast plain, and Great Plains) causes it to be a birding location. Its unique network of resacas (distributaries of the Rio Grande and oxbow lakes) provide habitat for nesting / breeding birds of various types - most notably during the Spring and Fall migrations.