my thermometer must be broken

[SelkirkAlex]

temperature in my unheated poly tunnel was -5.9c last night but the one stuck on the outside of the kitchen window where there could be windchill reads -19.4c ridiculous!

[Snoop Puss]

Chilly, chilly!

[Mr Bones]

We dipped to minus 4.7, that's cold enough

[bikermike]

the forecast said -6 for us (at about 6 this morning). The thermometer at the tube station at 7.45ish said -3 but I think that gets more sun.

[chris_m]

temperature in my unheated poly tunnel was -5.9c last night but the one stuck on the outside of the kitchen window where there could be windchill reads -19.4c ridiculous!

It must be broken - wind chill doesn't affect thermometers, only objects with a built-in heat source. A dry thermometer can only read the ambient air temperature.

[Jay22]

I'm willing to be that where you are Alex the thermometer was right!!

[Kirk]

They put thermometers and hydrometers inside a Stevenson Screen in order to not get false readings from the effect of wind. As I guess SA didn't glue a Stevenson to his window it was very likely affected by the wind.

[MarkPelican]

A while ago there was a discussion as to whether a waterbutt of water in a polytunnel would help to keep it warmer. This morning my waterbutt was frozen solid (the temperature in the polytunnel had dipped to -3.1 and the outside temperature to -4.9)

[chris_m]

They put thermometers and hydrometers inside a Stevenson Screen in order to not get false readings from the effect of wind. As I guess SA didn't glue a Stevenson to his window it was very likely affected by the wind.

http://www.russell-scientific.co.uk/...eens-35-c.asp;

A Stevenson's screen is used to shield instruments from precipitation and direct heat radiation from outside sources. The screen allows air to circulate freely and provides a uniform environment in relation to the air outside the screen.

No mention of wind and, indeed, with all the sides louvred the wind will pretty well blow straight through.