Question for Non US Dopers on Temperature

I’m writing an application that will report the temperature of a thermostat. I plan on having a field that will indicate if it is C or F. In the US, fractions aren’t generally used for reporting casual (i.e. home) temperatures. Since centigrade degrees ar in larger increments I was wondering if non-US people say something like “I set the thermostat to 18.5 degrees”? If so, is it only in incfrements of .5 degrees or should I allow for .1, .2, etc.

I just realized how stupid this question probably sounds to a non-American :o

Not really. I set my thermostat to about 20, but they’re not really exact, ya know?

On the news, when discussing records, decimals are used. ie - 21.4, 26.8, etc, etc

I’ve never heard anyone refer to their home thermostat in a decimal.

I don’t think I’ve heard anyone refer to temperature in Celsius with decimals, except in very scientific-type settings. Like, when you really need to know if your liquid nitrogen is -212.6 or -212.7.

In common usage, which generally means weather, a specific celsius integer will be given, e.g. “it’s supposed to get up to 28 degrees this afternoon”, when the farenheit equivalent might be ‘low 80s’ (or whatever 28c equates to!). The impression I get is that current forecasting makes short-term predicitions to within a degree celsius to be realistic, whereas accuracy to a degree farenheit is some way off.

And who would expect a domestic thermostat and room temperature to be consistently and accurately maintained to within one degree of either scale?

Weather forecasts here are always given in Celsius, in whole numbers.

Despite many posts on the SDMB to the contrary, I defy anyone genuinely to be able to sense a genuine one degree of fahrenheit temperature change, and a Celsius-comprehender wouldn’t be able to sense a 0.5C change. Thermostats rarely have 0.5 increments.

Go for the whole numbers in C, and I don’t think there’ll be any complaint.

My car’s (2002 Hyndai Santa Fe) electronic controlled AC has 0.5 C increments. But generally, as others mentioned, we use whole numbers.

In the context of room or outside temperature I see decimals very, very infrequently - never on weather forecatsts, only occasionally when records of low or high temperature are reported.

Digital thermometers for consumer use sometimes show one decimal (pretty pointless IMO as their accuracy is much worse that 0.1 K)

Digital thermometers for body temperature always show one decimal, of course, and people pay attention to that decimal.

Thermostats - I wouldn’t expect to set temperatures in fractions of degrees, at least for a single-room or apartment thermostat. The car thermostats that I have seen also only showed integer Celsius values.

Where I’d consider tenths of degrees in room temperatures or thermostat settings significant is only with reference to running large buildings, where a difference of a tenth of a degree might make a significant difference in heating/cooling cost.

I can’t help suspect that this is a case of “oh shit, the display has an extra decimal place”…“don’t worry, just put in a .5 step and it’ll look like we’re being more accurate”

I have never seen a Celsius thermometer with decimal increments.

Well, what do you mean by ‘celsius thermometer’? Medical ones, both mercury and electronic, have plenty of smaller divisions.

I’m American but I reside overseas. None of the thermostats I’ve seen here is calibrated for anything other than whole degrees (C of course).

The climate control in my car is set by up/down buttons and a digital display with 0.5 celsius intervals, but only in the middle of the range; if you turn it way up or way down, the increments are in whole degrees. This must be intentional; furthemore, an adjustment of 0.5C does make a difference; you can hear the fan ramp up or down. I’m sure this is all academic though; the accuracy of the sensor isn’t actually going to be as fine and true as all that.

One on a house, or in my car.

Thanks all of you. An intersting thing I noticed in my Saab is that in Celsius mode the termperature control is in one degree increments and in Farenhiet it is in two degree increments. I expect that the designers thought “who needs more that ‘one degree’ precision”.

Second what **Mange’ ** said. My car is the same. You might consider 0.5 increments. You definitely do not need finer than that. Whether you even need half degree increments is distinctly dubious.