The northwestern Neotropical rattlesnake is a large species of rattlesnake found across much of southwestern Mexico. This snake inhabits a wide range of elevations from near sea level all the way to elevations of 2285m in the Sierra de Coalcomán. While it can be found in arid environments, tropical scrub forest, savannas and even mesic forests, rocky outcroppings are central to this species' habitat needs.
Crotalus culminatus has a myotoxic-hemotoxic venom which can cause hemorrhaging and induce localized paralysis via muscle damage. This makes it less deadly to humans than its close cousins; however, it can still cause lasting damage and even death. It is likely a generalist predator, with reported prey items including rodents, lizards and small birds.

The cincuate pine snake (Pituophis lineaticollis lineaticolis) has been proposed by some scientists as a possible Batesian mimic of Crotalus culminatus due to their overlapping range, similar defensive behaviors, and extreme pattern resemblance (particularly the neck stripes present in both species).

The name "culminatus" comes from the Latin words "culmen" (ridge) and "-atus" (provided with), referring to this snake's strong vertebral ridge.