This web system will allow you to easily download years of hourly weather data for any of the 26,361 weather stations in 261 countries. There is data going back to 1901 for some stations. I wrote this system to help my own energy consulting business get weather data for merging with utility data. This system is free to anyone who needs hourly weather data. All I ask is some feedback so I can improve it.

How this system works:

This system interfaces with google maps to make it easy to select weather stations in countries and states/provinces. The system will automatically retrieve mutiple years of data for a weather station and create a CSV file which you can then download. Currently there are 539,238 files of yearly data files for the stations.

This websystem interfaces with NOAA at ftp://ftp3.ncdc.noaa.gov/pub/data/noaa/ to obtain longitude/latitude, name and other station attributes. It also checks the ftp file directories once a night to check for file changes and updates a SQL database at KlosEnergy.com. The websystem then gives each year of data for a station a 'grade'. Green=good hourly data. Red=spotty hourly data. The websystem does NOT open each of the 500,000 files to determine record counts. It only estimates by looking at the file size and should only be used as a guide. NOAA does provide a station master list containing record counts, but I found the data to be somewhat unreliable. It would sometimes contain record counts for data files which do not exist yet.

NOAA will frequently have two stations at the same location. One station name will have older data and the other station will have newer data. PLEASE zoom in to see the two stations. I offset the icons so they don't overlay each other.

If someone retrieves data files for a station, the system will 'cache' those files to speed up requests in the future for the same station. Future requests for the same station will go much faster. Of course, the system will still have to FTP to NOAA to get the current year because those files are updated daily. The files will come to you GZ compressed. (The same compression that NOAA uses). Use 7-zip (my favorite) or WinZip to uncompress. The dates and times are UTC. At this time, you must adjust the date and time to the local time. In the future, I hope to have written a utility that will convert these for you. I'm still working on determining the time zone polygons for the world. If you see 9999 in a field, it means NOAA does not have a value for that date and time.

I wrote quite a bit of code (in SAS) to fix the station attributes. NOAA doesn't always list the state for USA data and for offshore stations, NOAA often will not list the country. My SAS code looks at each station and determines the best polygon (for a state or country) that the station is either in or nearest to. I found a few errors in NOAA's station attributes. You will find NOAA placing a New York station in Kansas or a German station in Sweden. I have a spreadsheet identifying these errors that is available upon request.

I am looking for feedback. Are you interested in other data than temperature and dewpoint? Need a CSV file showing how many hours for each temperature at a station? How about a way to find the best weather stations near a zipcode list? Please email me or call me at 920-864-2150. Phone calls are welcome.

A quick bio: I have been in computers since the late 60's. I still have a card punch machine in my shed and have a box of teletype tapes in my attic. Over the years, I have worked in APL, Fortran, Cobol, PL/1, CICS on mainframes and Assembler, Pascal, C++, SAS and PHP on PC's. I use SAS to analyze files having hundreds of millions of records for utilities and have written 25 web PHP/MySQL systems for scheduling, optimization and field data collection. Most of the systems are private and not seen by the general public. Call me if you wish to discuss them.