if the air temperature @ sea level were 23 C what would the air temperature be at a height of 2 km under avg conditions?

Since the normal lapse rate is 6.5°C per kilometer, at a height of 2 kilometers the temperature would decrease 13°C (6.5°C × 2 = 13°C). The air temperature at 2 kilometers would be 23°C - 13°C = 10°C.

try:

http://www.engineeringtoolbox.com/air-altitude-temperature-d_461.html
or
http://www.digitaldutch.com/atmoscalc/

10 degrees C

Well, if the air temperature at sea level is 23°C, it must be having a great time sunbathing! As for its friend 2 km above, well, let's just say it's enjoying a cooler breeze. On average, for every 1 km increase in height, the temperature tends to drop by about 6.5°C. So, at 2 km above sea level, we can expect a temperature that's around 10°C cooler than at sea level. Meaning, the air temperature at that height would be roughly 13°C. Brrr, better bring a jacket for that chilly altitude!

To estimate the air temperature at a height of 2 km above sea level under average conditions, you can use the Environmental Lapse Rate (ELR) as a guideline. The ELR is the rate at which the temperature decreases with increasing altitude.

On average, the ELR is around 6.5 degrees Celsius per kilometer (approximately 3.6 degrees Fahrenheit per 1,000 feet). This means that for every kilometer you ascend in the atmosphere, the temperature typically drops by 6.5 degrees Celsius.

Given that the air temperature at sea level is 23 degrees Celsius, we can calculate the temperature change by multiplying the ELR by the altitude difference (2 km).

Temperature Change = ELR * Altitude Difference

Temperature Change = 6.5 °C/km * 2 km

Temperature Change = 13 °C

To find the air temperature at 2 km above sea level, subtract the temperature change from the initial temperature at sea level:

Air Temperature at 2 km = Sea Level Temperature - Temperature Change

Air Temperature at 2 km = 23 °C - 13 °C

Air Temperature at 2 km = 10 °C

Therefore, under average conditions, the estimated air temperature at a height of 2 km above sea level would be approximately 10 degrees Celsius (50 degrees Fahrenheit).