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Does anybody know if there is a place I can find historical data of weather forecasts by forecaster? I'm mainly interested in forecasts of high temperature and low temperature, but precipitation forecasts would be great as well.

To clarify, I am looking for historical forecast data. For example, I would be interested in knowing what Wunderground said the weather forecast for April 20th was on April 16th. Essentially, I am looking to compare historical forecasts against the actual weather that occurred to see if different sources of forecasts have different biases.

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    This topic appears from time to time on this forum. Here are some past posts that have links to resources: opendata.stackexchange.com/questions/875/… , opendata.stackexchange.com/questions/1796/… , opendata.stackexchange.com/questions/297/… May 8 '14 at 13:11
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    What is the geographical scope of your request ?
    – magdmartin
    May 8 '14 at 13:38
  • I'm interested in global data, but even just getting data for the US would be useful. Andrew, it looks like those topics are mainly regarding realized historical weather data. I'm looking for data about forecasted weather. I'll modify my question to be clearer.
    – Eric
    May 8 '14 at 18:20
  • @Andrew-OpenGeoCode : I think those other questions were about actual weather reports, not forecasted weather. I suspect that many of these companies just repackage the National Weather Service's data
    – Joe
    May 9 '14 at 12:58
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    forecast.io (aka darksky.net) no longer provides historical forecasts. From their API FAQ on July 27, '18 (darksky.net/dev/docs/faq#previous-forecasts): > Can I get your previous forecasts instead of weather station observations? > > Unfortunately, we do not have the storage capacity to store previous > forecasts. Sorry!
    – randomDNA
    Jul 27 '18 at 12:41
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The NOAA / National Weather Service has an archive from the Weather Prediction Center, but it only started archiving most products a few years ago:

Most of what's archived are weather maps (like what you'd see behind the weatherman on the news as he's giving his forecast), and not specific temperatures. Their 'national high/low' product just reports where the highest & lowest temperature on a given day was recorded, not the high/low for lots of cities.

For many years, they only maintained a 'rolling archive', where they'd keep maybe 30-60 days of forecasts, and then purge them. It's possible that something like archive.org might have some of it, but it'd likely be an incomplete record. If you wanted to go that route, take a look at the list of NOAA's national centers:

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  • Thanks Joe. Do they still maintain the rolling archives? I didn't see them on the site, but I'm not sure if I was looking in the right place.
    – Eric
    May 9 '14 at 17:48
  • @Eric : I'm not at a place where I can FTP from, but the rolling archives were available via FTP. See nws.noaa.gov/tg/anonymous.php
    – Joe
    May 13 '14 at 16:32
  • dead links fixed! ref: opendata.stackexchange.com/q/13330/1511
    – philshem
    Sep 18 '18 at 10:57
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forecast.io also provides historical forecasts through their API. You can call a past date and time and still get the daily, hourly, and minute forecasts (in addition to actual forecasts). That is, ask for the weather on April 16th and will include forecasts for April 20th in the daily summaries.

It's free for under 1,000 calls per day, and then $1 for 10,000 calls--a pretty reasonable price.


Update

forecast.io (aka darksky.net) no longer provides historical forecasts.

From their API FAQ on July 27, '18 (https://darksky.net/dev/docs/faq#previous-forecasts):

Can I get your previous forecasts instead of weather station observations?

Unfortunately, we do not have the storage capacity to store previous forecasts. Sorry!


Update 2

Apple has acquired DarkSky and has closed new sign-ups for the API. This likely isn't a useful answer anymore.

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  • Darksky appears to have historical forecasts again: darksky.net/dev/docs#time-machine-request
    – Swier
    Oct 10 '18 at 14:24
  • This doesn't seem to actually be historical forecast data, as past data gives observed (not forecasted) values: "A Time Machine Request returns the observed (in the past) or forecasted (in the future) hour-by-hour weather"
    – bendman
    Nov 2 '18 at 19:40
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It seems that ECMWF (European Centre for Medium-Range Weather Forecasts) has archived forecast data, both as bulk downloads and even (maybe) as API. Perhaps you have to register.

https://www.ecmwf.int/en/forecasts/datasets/archive-datasets

Our Meteorological Archival and Retrieval System (MARS) enables you to list and retrieve meteorological data in GRIB/NetCDF via:

  • the MARS client on ECMWF computers such as ecgate
  • the Web API service (supported Python client software)
  • web interfaces where you can explore the parts of the archive available to you and get the MARS request syntax/scripts to download data on ECMWF computers or via the web API. Members and licence holders can also check availability of the data and estimate the download size.

YMMV - I haven't explored the data at all

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