How must a property behave to measure temperature?

For temperature readings to be accurate and meaningful, thermometers should be located five to six feet above the ground (ideally not over a paved surface) to minimize the effect that the underlying ground itself might have on temperature. Thermometers also should not be exposed to direct sunlight. The bimetallic strip or "bulb" of a liquid-in-glass thermometer absorbs solar radiation more efficiently than surrounding air, so exposure to direct sunlight causes it to measure a temperature that's higher than the surrounding air. To truly measure air temperature, a thermometer should be in the shade, where the temperature of the thermometer itself should be the same as the air temperature. Finally, thermometers shouldn't be located too close to buildings since warmth from buildings (via emitted radiation or the escape of air through vents, etc.) could contaminate the temperature reading.