Atmosphere, air pressure and air temperature

Air temperature shows how warm or cold the air is and is measured with a thermometer in °C. At weather stations the thermometer is placed in a special screen about 2 m above the ground, in the shade, open to the air, with its door facing north so the Sun’s rays do not fall on the thermometer. Temperature is read several times a day (for example every 3 hours, i.e. 8 times). Daily mean = sum of all readings ÷ number of readings. Monthly mean = sum of the daily means ÷ number of days in the month; annual mean = sum of 12 monthly means ÷ 12. In the troposphere the temperature falls about 6 °C for every 1000 m of height (0.6 °C per 100 m). It also depends on latitude: at the equator the Sun’s rays fall almost straight down and it is hot, at the poles they fall at a slant, so it is cold.