Why is outdoor temperature always taken in the shade as oppossed to the direct sun?

Answer 1

I think to get the median temperature

Answer 2

Ambient air temperature is the universally recognised outdoor temperature reading and while some older technology used for thermometrics is still used and would affect the temperature in the way other writers have detailed, newer digital thermometrics are made of plastic and other materials that absorb far less radient heat. The primary reason is that radiant heat affects all objects it contacts with an equal volume of radiation, including the tiny particles in the air. When these particles heat up, the air around them is heated up more than it otherwise would in the shade, so the reading would be innacurate as per the recognised temperatre reading protocol mentioned. Relative to the measurements taken in other locations, the protocol must be kept universal so readings are comparable and statistically sound for historical records and weather prediction purposes, among others. If readings were taken in the sunlight then there would be a massive difference between the reading taken in the sun, and the reading taken in the shade of a cloud, the moon, or at night time.

Answer 3

The best way to measure temperature is actually in an open area exposed to sunshine but with the temperature sensor shadowed and ventillated. It should be over grass or natural ground cover and away from artificial surfaces such as blacktop which absorb more heat than the surrounding area. The best instruments have the sensor placed in a tube and air is gently blown across it from the horizontal at a height of 2 meters. That way the ambient air temperature at sensor level is measured but not the effects of radiation (solar or terrestrial) on the sensor to any significant extent. I.e., the effects of the ground exposed to sunshine heating the air should be measured, but the sensor should not be exposed.

Of course, you can place the sensor wherever you want for what you want to measure. E.g., if you want the temperature in a shaded area (e.g., under a group of trees) rather than a nearby open area, you can certainly place the sensor there instead. FWIW all temperature measurements the NWS uses at airports are in open areas using a ventillated sensor in a reflective tube.

Answer 4

Then temperature given by trained meteorologists is an average temp. It takes into consideration positions that are in direct sunlight, partial obstruction of the direct rays, and total obstruction of the direct rays. Not quite an exact science, as location is always the mean. It has everything to do with where your measuring instruments are located. I have merc thermos located front and back of my homestead. Also digital thermos same proximity. Varies always. I live where it hit 122 degrees June 8th. Laughlin,NV. Find it.

Answer 5

The actual receptor ball of the thermometer, such as the metal part of a houshold thermometer, which, when heated, drives up the reading fluid by expansion, such as mercury, would over heat beyond the ambient, or actual average air temperature and give a falsely high reading.

Answer 6

the shade will provide ambient temperature... direct sunlight would make the temp higher coz of the radiation from the sun.

Answer 7

That is just common sense. That is like asking why you don't measure the indoor temp. in you house by placing the thermometer in front of the oven.

Answer 8

ambiant temperature includes moisture....taking the temperature in direct sunlight would cause false readings