Is there a database of airport ceilometer raw data?

I am interested in obtaining raw ceilometer data, to test some cloud/aerosol layer identification algorithms.

• Is this type of data freely available or will I need to ask for it directly from the airport?
• Do airports keep an archive of raw data or simply of cloud heights as determined by manufacturers algorithm and provided in METAR reports?
• I think that would be best done in cooperation with meteorological department of nearby university. – Jan Hudec May 7 '15 at 14:47
• I am working for the meteorological department of a nearby university :) The thing is that I wanted to know if there is some kind of freely available online database. Anyway, I will contact the local airport and meteorological service, and see what they can do to help me. – luka May 8 '15 at 9:29

OGIMET looks like it goes back to 2005.

My favorite weather site Weather Underground has historical data.

It seems like you need to plug in dates one at a time but there are plenty of ways to skim a page and im sure you can ask them for a data dump if you know what you need.

• Thank you! I already knew about these websites, and they are very good at what they do, but I couldn't find what I was looking for in their archives. They have METAR reports which will be useful when ceilometer manufacturers' algorithms are compared to mine, but I still need the raw data to put my algorithms to use. – luka May 8 '15 at 9:33
• @WizardInBlack it may be worth reaching out to Wunderground and asking if you can pull some of their raw data, ya never know, they might let you. – Dave May 8 '15 at 13:39
• I accepted your answer as the most useful one. I am still waiting for answers from Wunderground and Ogimet. – luka May 13 '15 at 10:16

Weather Underground is a great site, although finding the specific link for archived METAR reports is more difficult than it should be. The following link is an example that gives all METAR reports for a given airport on a given day; you can either use the fields given on the page to find other dates & other stations, or you could edit the URL itself to find what you want (and perhaps even automate that into a screen-scraping app): Weather Underground Link

You can also get the same data in a CSV file with a separate link.

If you don't mind doing a little bit of coding, you can also subscribe to their API, which allows you to get historical data with some fairly straightforward calls to their API. The "developer" subscription is free but limited in how many calls you can make; more expensive subscriptions allow more calls. The following link is where you can start learning about their API.

((This answer is as much an answer to this question, which is now closed and marked as a duplicate of this one. It is a slightly different question, and this answer is really more aimed at that question, but it addresses this question as well.))

• Weather underground does not provide CSV data for free any more :-( – trapicki Mar 2 '18 at 19:17

I have been looking for this kind of historical data for a long time, and I finally found it!

Check out Iowa State University of Science and Technology's site, called IEM (Iowa Environmental Mesonet). There is even a python script you can use to download it programmatically if you wish! It has various forms of data (maybe not for all networks) going back to 2000 for ASOS and 1995 for AWOS.

It has worldwide data, you just have to switch to the network you want and choose the reporting station!

The NCEP Meteorological Assimilation Data Ingest System (MADIS) data archive has global METARs going back all the way to March 2006. If you're interested in just the US, you can find data for 2001 through 2020.

For example, here are the hourly METAR files for June 6, 2011.