Calculate the air temperature at an altitude of 1850 m, given that at 150 m it is +23°C.

Using the rule that for every 100 m of altitude, the temperature decreases by approximately 0.6°C: Altitude difference = 1850 - 150 = 1700 m. Temperature decrease = 1700 * 0.6 / 100 = 10.2°C. New temperature = 23 - 10.2 = 12.8°C. Answer: 12.8°C.