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Comment by metaphor | Hacker News Reader

> Accurate (within 3deg F) weather predictions

Sniff test: ASTM E230 standard tolerances for the venerable Type K thermocouple is +/- 2.2°C or +/- 0.75%, whichever is greater.

Expectations are in need of recalibration if anyone thinks a single number is going to meaningfully achieve that level of accuracy across a volume representing any metro area at any given point in time, let alone two days out.

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I am not sure if type K thermocouple are used for meteorological air temperature measurements.

These sensors (based on thermal resistance) for example have an accuracy of 0.2 °C under typical conditions [1].

[1] https://www.ti.com/lit/ds/symlink/tmp1826.pdf?ts=17427997638...

That is the accuracy of one sensor. The law of large numbers comes into play when using forecasts such as this, since accross any reasonably sized metro area you will have hundreds if not thousands or even tens of thousands of weather stations, accross which you can average to bring down error thresholds.

I think you misunderstood the assignment. The temp predictions in my area wildly swing around, until the day of, and even then I have to adjust for my actual location. And I'm not in Kansas City. The only place that has ~3° accuracy is San Diego. And maybe Antarctica.

The bigger the volume the more accurate temperature you should be able to get.

Do you think 2C global warming is irrelevant because a single thermocouple couldn't accurately measure it?

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