In order to prevent direct sunlight falling on and affecting the instruments when the door is opened it is designed so that the door opens to the north in the northern hemisphere. This is because the Sun never shines from the north.
It is painted white to reflect incoming radiation from the Sun and is set at a height of 1.25 metres above the ground, so as not to be affected by the Earth's low-level radiation. The screen should be kept clean from dust and dirt.

The thermometers inside are usually the dry bulb, wet bulb, maximum and minimum. They are read in that order.

The dry thermometer is a mercury filled thermometer, recording changes in temperature in degrees and tenths Centigrade. The temperature rises and falls as the temperature changes. This is the air temperature reported on TV and in the press. The wet bulb is an ordinary thermometer with a muslin wick covering the bulb. This is fed by water from an adjacent reservoir. The comparison between the dry and the wet bulb temperatures enables the DEW POINT and relative humidity of the air to be calculated.

The maximum thermometer is filled with mercury, which moves up the central tube as the temperature increases. There is a constriction just above the bulb of the thermometer, which stops the mercury returning to the bulb when the temperature falls. Therefore, the highest temperature (the max) is recorded regardless of the temperature at the observation.

Check the automatic weather station data here.
This part of the website is the responsibility of the Meteorology Instructor.