How does the climate change along the course of the Rio Grande?

The climate along the Rio Grande transitions significantly as the river flows from its high-altitude sources toward the Gulf of Mexico.

In its upper reaches within the San Juan Mountains of Colorado, the river begins in a forested, high-elevation environment. As it moves south through New Mexico and into the Basin and Range and Mexican Plateau provinces, the combination of declining elevation, decreasing latitude, and increasing aridity drives a shift in climate. The region transitions from a cold steppe climate—characterized by vegetation such as piñon pine, juniper, and sagebrush—to a hot steppe and desert climate. This arid landscape is dominated by desert flora, including mesquite, creosote bush, cactus, and yucca.

Following this transition, the river continues through the "big bend" region and eventually traverses the Gulf Coastal Plain before terminating in a fertile delta at the Gulf of Mexico.1