Weather forecast accuracy
Sunday, June 19th, 2011 10:15 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
lethargic_manOne of the subjects with which I disagree with ![[livejournal.com profile]](https://www.dreamwidth.org/img/external/lj-userinfo.gif)
livredor is the utility of weather forecasts. livredor holds they're useless and there's no point paying any attention to them; by contrast, I rely on them to know whether to take waterproofs with me when I'm cycling to work, and they rarely let me down.
After the last time we disagreed over this, I thought: this is something that can be objectively proved one way or the other: I can write a little program which fetches the weather forecast from the Met Office website, sees how many times the Met Office change it, and then gets the recently-observed weather data to tell whether yesterday's forecasts are accurate or not; and then puts the data together into reports with pretty graphs and things.
This sat on my to-do list for rather a long time, but eventually percolated to the top, and I started writing such a program. An hour and a half in, I thought: this is silly; I'm sure somebody else must have done this already. And indeed they had. (And so, in this age we live in, there's never any point doing anything because not only has someone done it already, but they've put the results up on the World Wide Web where it's only a google away.)
Anyhow, the results were surprising (for me at least). I was expecting a higher accuracy than 55% for the one-day forecast. (And this page seems to say the four-day forecasts are more accurate than the one-day ones; I think this shows they're not using enough data. OTOH, what I remember from looking at other pages last week seems to generally corroborate this one, so it's not complete rubbish.) On the other hand, it does show the forecast is rarely completely wrong.
The other surprising thing is that they said the BBC was more accurate than the Met Office. Aren't the BBC supposed to get their data from the Met Office? In any case, I find it's generally the other way around: The two don't always agree, and I tend to go straight to the Met Office website to get my data from the horse's mouth. (Bet you didn't know horses could forecast the weather...)
livredor is the utility of weather forecasts. livredor holds they're useless and there's no point paying any attention to them; by contrast, I rely on them to know whether to take waterproofs with me when I'm cycling to work, and they rarely let me down.After the last time we disagreed over this, I thought: this is something that can be objectively proved one way or the other: I can write a little program which fetches the weather forecast from the Met Office website, sees how many times the Met Office change it, and then gets the recently-observed weather data to tell whether yesterday's forecasts are accurate or not; and then puts the data together into reports with pretty graphs and things.
This sat on my to-do list for rather a long time, but eventually percolated to the top, and I started writing such a program. An hour and a half in, I thought: this is silly; I'm sure somebody else must have done this already. And indeed they had. (And so, in this age we live in, there's never any point doing anything because not only has someone done it already, but they've put the results up on the World Wide Web where it's only a google away.)
Anyhow, the results were surprising (for me at least). I was expecting a higher accuracy than 55% for the one-day forecast. (And this page seems to say the four-day forecasts are more accurate than the one-day ones; I think this shows they're not using enough data. OTOH, what I remember from looking at other pages last week seems to generally corroborate this one, so it's not complete rubbish.) On the other hand, it does show the forecast is rarely completely wrong.
The other surprising thing is that they said the BBC was more accurate than the Met Office. Aren't the BBC supposed to get their data from the Met Office? In any case, I find it's generally the other way around: The two don't always agree, and I tend to go straight to the Met Office website to get my data from the horse's mouth. (Bet you didn't know horses could forecast the weather...)
