OT:Weather to pot ...

[Jethro_uk]

BBC says maximum 4C today - thermometer is reading 10 !

[Georg von Krapp]

I'd say get a new thermometer. The BBC are rarely wrong about this sort of thing. Or, indeed, any sort of thing.

[Jethro_uk]

:)

[Bob H]

4.4C here in Leeds

[Andrew Gabriel]

Measuring outside temperature is not easy.

In the shade, but in the middle of a sunny lawn, I have 7.5. Similar over a lawn which hasn't yet had much sun, it's 5.

In the sun, it will be much more.

[bod]

6 here in Iver, Bucks.

[Bill]

In message , Georg von Krapp writes

But, to be serious, last night the temperature outside read -2C, but when I pointed my trusty Maplin pointy thermometer, which is usually about right, at the North side of the Disco, it read -9C.

Why would this be?

[Jethro_uk]

When I first got the toy (end-of-range at Maplin ;) ) I put the outside sensor in the path of the morning sun ... I did wonder why it was reading

30 most days

To be honest it's a little gimmicky. Knowing what the *temperature* is outside has very little to do with how it *feels*. A slight breeze in 3C can be colder than a still -3C

[ARW]

Minus 28 in Barnsley according to the display on my van dashboard!

[Dave Plowman (News)]

Is it north facing and shaded from the sun?

[Andrew Gabriel]

You might want to lookup a Stevenson Screen.

Wind and humidity are big factors. The wet bulb temperature is more useful as a measure of comfort, but doesn't work at low temperatures.

[Jethro_uk]

It is shaded from the sun now (see previous post). However, thinking about it, above it's mounting, the roof is (black) felted, so it's possible, as it's quite still, that a little tiny pocket of warm air is enough to skew it.

[David.WE.Roberts]

Thermometer reading 4.2C.

Hail bouncing off the lawn.

Met Office predicts 5C and rain.

[Dave Liquorice]

Point your pointy thermometer at the clear night sky and it'll be -50 ish. The Disco will radiate heat and without cloud cover it just disappears out into space. Thus the car just gets colder and colder trying to reach equilbrium with the -50... Normally at some point there will be enough heat from other sources to prevent the car from cooling too far down but surface temperatures can easily be 10 or more degrees below air temperature. Hence getting a ground frost without an air frost.

[harry]

Thermometer has to be in the shade to get a true reading.

[harry]

Radiation loss. Nearby buildings reflect heat.

[The Natural Philosopher]

5C at lakeheath RAF base they reckon.

And hail..

[The Natural Philosopher]

Its da black body radiation, mon.

[The Natural Philosopher]

Thats the speedometer dear.

[Bob Martin]

You have an IQ meter?