In the 25 miles (40 kilometers) between the NCAR mesa and the highest Front Range peaks to the west, the climate undergoes a drastic change. At mountaintop, above 13,000 feet (4,000 meters), the climate resembles the Arctic more than the Great Plains. Slow-growing mosses, lichens, and tiny perennials are the only plants that can survive.

Even the smaller mountains visible behind the NCAR mesa tend to be cooler than the mesa itself. The top of Bear Peak is 8,461 feet (2,579 meters) high. On most summer days, Bear Peak is 5-10 degrees F (3-6 degrees C) cooler than the mesa. However, the peak can be warmer than the mesa when an inversion traps cool air at lower levels.

Just one or two degrees' difference in average temperature can determine a plant's survival. At the same time, plants can affect the air temperature around them by absorbing or reflecting sunlight.