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  Citizens Weather Observer Program (CWOP) Data

Citizen Weather Observer Program (CWOP) Data



The Citizen Weather Observer Program's (CWOP) data is quality controlled through MADIS. The program is made up of ham radio operators and other private citizens around the world that have volunteered the use of their weather data for education, research and use by interested parties. The APRS-IS servers collect weather data transmitted from individual stations and communicates these data to the amateur radio findU server where the data are organized and made available to the MADIS Program at 5 minute intervals.

CWOP was originally set up to provide data only from automated weather stations. Now, in collaboration with MADIS and the Community Collaborative Rain, Hail & Snow Network (CoCoRaHS) the capability has been added to contribute observations of snowfall and snow depth that are taken manually, then entered into the database via a simple form on the MADIS website. We are asking anyone who wishes to participate to join CWOP and contribute snow observations -- you don't need to be an existing CWOP member or even have an automated weather station. All you need is an Internet connection and a Web browser!

CWOP is a public-private partnership with three goals:
  1. To collect weather data contributed by citizens.
  2. To make these data available for weather services and homeland security.
  3. To provide feedback to the data contributors so they have the tools to check and improve their data quality.
In fact, the web address, wxqa, stands for Weather Quality Assurance. CWOP has been sending data to MADIS since MADIS started on July 1, 2001.

Geographic Coverage


Data Schedule

Data arrive every 5 minutes. The current and previous hour's data are processed every 5 minutes. Data are stored based on thier observational time stamp in netcdf files that contain observations from the top of the hour until 59 minutes into the hour (e.g., the 0000 file covers 0000 - 0059).

Data that arrive after 2 hours following the time of the observation are processed in a "data recovery" mode, where once a day batch processing is performed to reprocess data that are 35 day's, 7 day's old, and 1 day old. These data are available with all communications methods supported by MADIS except for ldm.


Typical daily volume for all MADIS datasets can be seen here.


No restrictions. All observations are publicly accessible.

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Last updated 27 June 2017