• The PM2.5 numbers in Windy are way to high in the United States when looking at a specific location. The photo shows Sweet Home, Oregon. You can see the monitor reading of 412 under the flag, which is fairly close to other sites in Oregon, but the flag shows 1221! Why is the whole area in the dark maroon color shown with that color when there are areas within it with lower readings?

    Sweet Home Oregon in Windy - PM25.jpg

  • Sailor Moderator

    This map is from satellite sensors data and forecast weather model. Where there is an Air quality station it is surely better to rely on it.
    Concerning the color scale, you can modify it and add one more step or several above 300μg/m3.



  • I already tried changing the colors using listings of a 1000 at the high, but it still basically looks the same. It seems the data being used is the really high numbers I listed. I am new to windy.com, and I am finding a number of problems. I don't think I can trust what I am seeing.

  • Here is a contour image from airnow.gov, and it seems much more accurate.airnow-contours.jpg

  • Sailor Moderator

    @UnderwaterSurfer said in PM2.5 is way to high!:

    I already tried changing the colors using listings of a 1000 at the high, but it still basically looks the same. It seems the data being used is the really high numbers I listed.

    Of course changing the colors does not change the values on the map.

  • It changes the color that is displayed for a given value that is in their data. If I put 1000 at the lowest setting then it changes what is displayed to blue. The data being used is wrong, so how can anybody trust this site? The developers are the ones who setup everything, and a default of the high being 300 is not good. It should be 600 in my opinion based on what I am seeing on so many sites. I live about 15 miles away from one o the major fires in Oregon.

  • I am now seeing PM2.5 data that is much closer but still a little high. The sensor in my city is reading at 499, where it is listed on Windy.com at 566 in the 1st photo, and now at 579. The defaults for the colors are still at a high of 300, which is not high enough. I changed mine to 500, 350, 200, 100, 50, 25, 0. Those changes produced this image.


    Look at the image for the entire world to see how bad it is for the west coast of the United States, with the worst being in my area.

    windy 2.jpg

  • Another issue I am seeing on Windy.com is that they have the visibility for my city at 23.5sm, when it is probably .5 to 1. We currently have heavy fog and heavy smoke If the data isn't correct then the site loses credibility. I would like it to be very accurate as that helps everyone!

  • The data is way off again, as it is at 808 right now, while the actual sensor is at 497. I can't trust Windy.com to provide accurate information. It looks nice!

  • Today there has been a reduction in PM2.5. In my city it is 223, but on Windy it shows 86! Now it is way to low. Please people don't trust what you see on Windy if you care about your health. Maybe they can fix their data problems and be more accurate in the future.

  • Hello @UnderwaterSurfer, we visualize forecast data, not the real-time situation.
    In case of PM2.5 –  this serves as a general overview, sudden events like fires, etc. that change the air quality, cannot be forecasted.
    Have you checked Air quality stations? Those are reporting data in real-time :)

  • Hi Petra,

    I am reporting the true readings from the sensor in my city, and can see the readings from many sensors all over the United States. On your site you are showing a current level for my city, and it isn't forecast data. When I first posted this I was seeing forecast PM2.5 data showing over 3,000 on Windy.com when I looked at it a few days in the future! What help is that to people? Why don't you put a big disclosure statement on top of your site stating that this is only forecast data and probably is not very accurate, so please don't use it to make any decisions regarding your health. The wind data seems accurate, as far as I can tell by comparing it to many other sites. This isn't a game! If you are going to provide weather information for people, that which is displayed needs to be accurate. If you can't do that then remove the listing for which you can't provide accurate information, such as PM2.5!

    Be Well!

  • Hi Petra,

    One other thing I forgot to mention, is that the major fire that is 12 miles away from me, has been roaring for 8 days, so isn't in the category of "sudden events like fires". Forecast information is only valuable if the accuracy is validated by looking at it when the forecast date arrives. If the forecast is close then it is valuable, but if it is way off then it isn't. In fact it can actually be harmful. I am hoping that Windy.com wants to be recognized as a quality site and grow because of accuracy measured over time. Garbage in garbage out applies to the PM2.5 data.

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