What is the temperature behind the aircraft?
If you want to know what air temperature overboard liner, it is enough to remember school geography lessons: scientists have long been established that with each new kilometer of height, the air temperature overboard falls about six degrees.
That is, if you remember the readings of the scoreboard in the airport building, where the temperature was indicated, say conditionally, +15 °C (not very hot summer day), and your flight passes, according to information from the scoreboard in the aircraft cabin, at an altitude of 10,000 meters, it is enough to multiply in the mind of 10 km on 6 degrees and fade «Earth» 15 degrees, you will succeed45 °WITH. Not bad for the summer day!

It should be borne in mind that the air temperature with height changes in different layers and the cases are still different. Therefore, it is better to trust in this matter of the information that the airliner pilot will be informed on the internal broadcast, or the one that is displayed on the monitors showing the flight (they are in many modern liners). In general, all of them report exact data on the temperature overboard based on the testimony of external sensors.
And yet, until the height of 10-15 km, the air temperature falls first, and then gradually grows up to 50-60 km, and then falls again…