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Comment by Tepix | Hacker News Reader

One (rather easy?) thing I'd like to see in weather forecast apps is a confidence score.

I know that sometimes the weather is hard to predict. Right now I can't tell by looking at the weather forecast how confident they are. If the different weather models give significantly different forecasts, the confidence score should reflect it.

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Just as an extra datapoint, when it comes to ocean racing, one of the biggest complaints about mesoscale weather data is that it does not have a confidence score. The weather forecast says that the north pacific high is going to shift 200 miles west, which changes your fastest course from San Diego to Hawaii from a west then southerly route, to a south then westerly route (the high pressure system sits directly in between)... if the confidence on this forecast is 95% then you know to commit to the southerly route, but if it is only 51% confidence and typically the high is 500 miles more east than this then you might make a different decision and monitor the situation as it develops.

Anyways, if anyone at the NWS is reading this, we do actually pay close attention to this stuff and a confidence score of some sort would make boat weather routing software a whole heck of a lot more accurate.

I have worked at my nation's meteorological office and they (and I'd assume others do too) provide this service. They do this by running an ensemble (at our office, a population size of 50) with different starting conditions of numerical weather prediction models, rather than a single run. This will give you a confidence in the predictions of the numerical models. Besides general forecasting, they are also using this for hazard triggers so it can basically answer questions like "In the next 72 hours is there a 50% or greater chance that wind speeds will be higher than 30 knots at the biggest airport?".

The Dutch weather forecast has an 'expert' forecast that includes confidence bands, see:

https://www.knmi.nl/nederland-nu/weer/waarschuwingen-en-verw...

The page is not very popular though

That's great, I would love it if there was something like that that covered a wider area.

Thanks, never new that service existed. They should advertise it more

I've an informal method for estimating uncertainty by looking at how the forecast for a particular day changes over time - i n the UK the BBC provides 10 day forecasts so I watch particular days and if they are consistent over time then I usually have more confidence than if the forecast for a particular day changes every day.

Mind you - I had a six hour walk in rain and snow last Saturday when the forecast was for a fairly nice day and had been for over a week :-)

The Climendo app takes an average of 3-5 forecasts and presents a confidence measure.

Not as good as proper confidence from the model ensemble, but better than what you normally get from a single forecaster.

There's a web interface too.. https://climendo.com

Take a look at the probability forecast that the Norwegian met office make available as an api - https://api.met.no

The National Weather Service office in Binghamton, NY publishes probabilistic snowfall forecasts that do a good job of breaking down the confidence scores (presumably other offices do this as well, this is just the one I'm familiar with).

There's no snowfall in the forecast at the moment, but you can see how it's broken down: https://www.weather.gov/bgm/winter

I don't like how they give you the worst possible weather for the day, for the whole area.

any biomes have a rain shower from one cloud over one neighborhood, but the whole area is now "chance of rain 100%", when the real user experience is 100% sunny/clear at all hours of the whole day

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