Thermometer

[MWB]

I have an indoor/outdoor thermometer. The thing itself is inside & the lead is under the door into a partly enclosed porch. Not in direct sunlight.
The temperature is 27 degrees cel according to the radio & TV news. And my neighbours, etc are saying how hot it is.
But my thermometer is only showing 22.4 for inside & 20.6 for outside. Why, when it is this hot, is my thermometer showing much lower?

[wildwood]

Providing the thing is working ok...... The meteorological temperature is usually taken in a white wooden box with louvers to keep a fair airflow and roof to keep the direct sun off. As you will appreciate, the outside temperature fluctuates a lot more than inside a building so your sensors are probably showing the correct temp at the spot where the sensor is. You can not expect a home thermometer to show the broadcasted temp all the time as their situation is very different.

[mibn2cweus]

As a quick check you could set your outdoor probe in a cup of ice with just enough water to cover the sensor. If the water is pure (no salt) the immersed probe should provide a reading of zero degrees.

If the thermometer passes that test then you might want to try the meat drawer test. Set the whole thing is an isolated thermally stable area for an hour or so to allow the assembly to reach equilibrium then compare readings.

Note: Drowning the whole meter in water is not advised.