According to the invention, a climate-related, or to be precise, a temperature-related correction of the altitude reading is carried out on an altimeter. In doing this, the measurement of altitude is based on an average reference temperature value at sea level and on an average air pressure reference value at sea level according to the U.S. Standard Atmosphere 1976. The correction ensues by altering the reference temperature at sea level. A correction is then carried out when the temperature prevailing at a certain altitude above sea level differs from the temperature reference value for this altitude. This temperature reference value results at sea level based on the average temperature reference value.