If you visited Mount Shasta City (elevation 900 m [3000 ft.]) and found the outside air temperature to be 27°C (81°F), what would be the air temperature at the summit of Mount Shasta (elevation 4200 m [14,000 ft.]) at that moment-assuming that the temperature conditions with altitude change at an average, or normal, lapse rate?

5.9°C

Explanation:

Summit height = 4200 m = 4.2 km

Ground height = 900 m = 0.9 km

Height above the ground = 4.2 km - 0.9 km = 3.3 km

the average or normal lapse rate is expected to be 6.4°C/km.

the temperature at summit of mountain would be =

= Temperature at ground - [ (4.2 km - 0.9 km) * lapse rate]

= 27° - [ 3.3 * 6.4° ]

= 27° - 21.12 °

= 5.88°C

≈ 5.9°C

Hence, the air temperature at the summit is 5.9°C