Integrate Your Weather Station with CWOP: A Practical Guide

Integrating a weather station with the Citizen Weather Observer Program (CWOP) lets you share accurate, real‑time data with the National Weather Service and the public.

In this guide we’ll walk through:

1. What CWOP is and why it matters
2. Connecting a Raspberry Pi‑based Solar‑Powered WeatherPi to CWOP
3. Required software and configuration
4. Registering your station with CWOP
5. Viewing and verifying your CWOP data

And, of course, enjoy the process!

SwitchDoc Labs is pleased to offer 10% off all our products to Instructable readers: use code 6NOFQ9UW at Amazon.com and 672E608 at Tindie.com. Offer ends September 3, 2015.

What is CWOP?

CWOP is a global network of privately owned weather stations, primarily in the United States but also in over 150 countries. Volunteer stations, such as the WeatherPi, send automated surface observations to the National Weather Service. These data feed the Rapid Refresh forecast model, providing 3‑ to 12‑hour predictions across the lower 48 states.

After passing through a comprehensive quality‑control pipeline, CWOP observations are distributed to the public. The network originally grew out of amateur radio packet experiments and now includes most Internet‑connected stations. As of July 2015, more than 10,000 stations report regularly to CWOP.

Step 1: Signing Up for CWOP

Registration is straightforward:

1. Obtain your DW designation number at wxqa.com/SIGN-UP.
2. Enter the DW number in the WeatherPi configuration file.
3. Follow the remaining steps in this guide to power up your station.

Useful links:

• Official CWOP portal: wxqa.com
• Check your station’s status: findu.com (replace EW766 with your DW number)
• Data quality checks: APRS‑WX Quality Control
• Station details: Gladstone Family Weather

Step 2: The Solar‑Powered WeatherPi

The WeatherPi is a fully solar‑powered Raspberry Pi weather station designed by SwitchDoc Labs. It offers:

• Measurement of 20+ environmental parameters
• On‑board MySQL database for historical data
• Solar‑system diagnostics (brownout detection, power monitoring)
• Remote configuration and data export
• Optional SMS, Twitter, or web output
• iPad‑based control panel
• Easy integration with Weather Underground, Twitter, etc.

Read the full build instructions on the WeatherPi Instructable.

Step 3: CWOP Interface to WeatherPi

Communication with CWOP uses the Automatic Packet Reporting System (APRS), a protocol that originated in amateur radio and now serves many real‑time data applications. The WeatherPi software leverages Tom Hayward’s pywxtd APRS libraries to transmit observations.

Step 4: CWOP Code in WeatherPi

The CWOP module reads sensor data and sends an APRS packet every 15 minutes. Below is the core function call:

# every 15 minutes, build new graphs
if ((secondCount % (15*60)) == 0):
        # print every 900 seconds
        sampleWeather()
        sampleSunAirPlus()
        doAllGraphs.doAllGraphs()
        # send our CWOP data
        # wind direction - degrees from true north
        # wind speed - integer MPH
        # wind gust - integer MPH
        # temperature - degrees F
        # rain since midnight - hundredths of inches
        # humidity - % where 100% = 00
        # pressure - 5 numbers in tenths of millibars
        CWOP.post_CWOP(
            wind_dir=currentWindDirection,
            wind_speed=currentWindSpeed,
            wind_gust=currentWindGust,
            temperature=CtoFInteger(outsideTemperature),
            rain_since_midnight=0,
            humidity=convertHumidity(outsideHumidity),
            pressure=int(bmp180SeaLevel*100+0.5)
        )

For more details, visit the original Instructable: Join the IOT with your Weather Station – CWOP.

Related Projects

• Software CWOP integration