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This is exactly what I found it didn't work for. I live in Seattle, and basically gave up on it (with today's news, I'll uninstall it from my Android phone). I

by girzel 7y ago

This is exactly what I found it didn't work for. I live in Seattle, and basically gave up on it (with today's news, I'll uninstall it from my Android phone). I could look out the window at steady rain, and Dark Sky would still be telling me it was going to be clear all day. Like that more often than not.

beoberha 7y ago
I live in Seattle now but used to live in Ohio. I agree that the minute by minute is pretty much useless in Seattle but it was incredibly accurate in Ohio. I have numerous stories where I was able to get to shelter or remain sheltered minutes before a sprinkle turned into a downpour. I know nothing about weather, but I have to assume the weather patterns in Seattle are just very difficult to predict or analyze at such a fine granularity.
- starpilot 7y ago
  The weird thing I know someone who swears by Dark Sky in Seattle, while for me it's been pretty inaccurate. I think these personal takes are plagued with confirmation bias.
crazygringo 7y ago
That's bizarre but actually can't be Dark Sky's fault. Switch to radar view in the app and it will show you the exact geographical distribution of rain in your city right now. This comes from national weather data. If that's inaccurate then something is wrong with the government data. Or maybe Seattle rain is somehow much patchier at a finer level than government data is able to resolve? FWIW in New York City its assessment of the next five minutes has always been literally perfect. It might say it's going to go from hard rain to nothing in two minutes... and it does, right on time. It gets increasingly noisy as you go to 15, 30, and 60 min out, though.
- starpilot 7y ago
  Radar data is hugely noisy and it can be difficult to suss out what is cloud cover with no precipitation, or what is precipitation, plus filtering out biomass and dust. All of these show up as radar returns. There can be shadowing. Dark Sky does its own pre-processing/denoising of radar and so that can lead to different results from NOAA.
  - crazygringo 7y ago
    Ah that's really interesting, thanks for the info. I'm curious then what users see in Seattle when it's raining out the window but the Dark Sky radar maps says it isn't. Are there swiss-cheese holes that are obvious processing artifacts? Is the whole city somehow below some threshold so it doesn't show rain anywhere? Are there patterns of extreme local variation in rain that get mistaken for noise and deleted? The solution is not necessarily simple, but identifying the culprit should be fairly obvious, no?
    - starpilot 7y ago
      Really recommend reading http://jackadam.github.io/2011/how-dark-sky-works/ http://jackadam.github.io/2011/how-dark-sky-works/ and https://en.wikipedia.org/wiki/Weather_radar#How_a_weather_radar_works https://en.wikipedia.org/wiki/Weather_radar#How_a_weather_ra... to get something of a handle on it For one thing, the resolution of radar is finite where one "pixel" (gate) is quite large, and everything under it is assumed to be constant. Precipitation at a spot on the ground is the result of everything happening from sea level up 40,000', and we don't have exact properties (temperature, dew point, humidity) for the atmosphere at all of those locations. We can fill in some gaps with models on supercomputers, but they're just models.
- ivirshup 7y ago
  This was my experience too. Perfect in Boston, recently great in Singapore, pretty much useless in Melbourne. I’d like to know more about their modeling. How much do they need to specialize on region for accurate prediction or data collection? Are varying prediction qualities based on different climates, or is it from bias in data collection?

by girzel 7y ago

beoberha 7y ago

I live in Seattle now but used to live in Ohio. I agree that the minute by minute is pretty much useless in Seattle but it was incredibly accurate in Ohio. I have numerous stories where I was able to get to shelter or remain sheltered minutes before a sprinkle turned into a downpour. I know nothing about weather, but I have to assume the weather patterns in Seattle are just very difficult to predict or analyze at such a fine granularity.

starpilot 7y ago
The weird thing I know someone who swears by Dark Sky in Seattle, while for me it's been pretty inaccurate. I think these personal takes are plagued with confirmation bias.

crazygringo 7y ago

That's bizarre but actually can't be Dark Sky's fault. Switch to radar view in the app and it will show you the exact geographical distribution of rain in your city right now. This comes from national weather data. If that's inaccurate then something is wrong with the government data. Or maybe Seattle rain is somehow much patchier at a finer level than government data is able to resolve? FWIW in New York City its assessment of the next five minutes has always been literally perfect. It might say it's going to go from hard rain to nothing in two minutes... and it does, right on time. It gets increasingly noisy as you go to 15, 30, and 60 min out, though.

starpilot 7y ago
Radar data is hugely noisy and it can be difficult to suss out what is cloud cover with no precipitation, or what is precipitation, plus filtering out biomass and dust. All of these show up as radar returns. There can be shadowing. Dark Sky does its own pre-processing/denoising of radar and so that can lead to different results from NOAA.
- crazygringo 7y ago
  Ah that's really interesting, thanks for the info. I'm curious then what users see in Seattle when it's raining out the window but the Dark Sky radar maps says it isn't. Are there swiss-cheese holes that are obvious processing artifacts? Is the whole city somehow below some threshold so it doesn't show rain anywhere? Are there patterns of extreme local variation in rain that get mistaken for noise and deleted? The solution is not necessarily simple, but identifying the culprit should be fairly obvious, no?
  - starpilot 7y ago
    Really recommend reading http://jackadam.github.io/2011/how-dark-sky-works/ http://jackadam.github.io/2011/how-dark-sky-works/ and https://en.wikipedia.org/wiki/Weather_radar#How_a_weather_radar_works https://en.wikipedia.org/wiki/Weather_radar#How_a_weather_ra... to get something of a handle on it For one thing, the resolution of radar is finite where one "pixel" (gate) is quite large, and everything under it is assumed to be constant. Precipitation at a spot on the ground is the result of everything happening from sea level up 40,000', and we don't have exact properties (temperature, dew point, humidity) for the atmosphere at all of those locations. We can fill in some gaps with models on supercomputers, but they're just models.
ivirshup 7y ago
This was my experience too. Perfect in Boston, recently great in Singapore, pretty much useless in Melbourne. I’d like to know more about their modeling. How much do they need to specialize on region for accurate prediction or data collection? Are varying prediction qualities based on different climates, or is it from bias in data collection?