What is CoCoRaHS? CoCoRaHS — Community Collaborative Rain, Hail and Snow Network — is a free volunteer weather observation network where home observers submit daily precipitation readings that go directly to NOAA, the National Weather Service, and local water utilities. The Stratus Precision Rain Gauge is the official CoCoRaHS gauge. Anyone with a Stratus gauge and 2 minutes a day can join and contribute data that helps farmers, emergency managers, and communities understand what's actually falling in their area. Made in USA.
Tom's Quick Answer: I joined CoCoRaHS three years ago. I check my Stratus gauge every morning, enter the reading online, and that's it. My data goes into the national precipitation database. It takes 2 minutes and the data is genuinely useful to people who depend on accurate local rainfall information — farmers, water utilities, flood managers. It's the most useful thing I do with 2 minutes a day.
Tom's Real-World Advice
I started using a Stratus gauge for my garden. I joined CoCoRaHS because it made the data useful beyond my own tomatoes. There's something satisfying about knowing that the reading I take every morning contributes to something larger — that a farmer 10 miles away or a water utility manager is using data from my backyard to make real decisions.
CoCoRaHS has over 20,000 active observers across the US. The network fills in the gaps between official weather stations, which can be miles apart. A thunderstorm that drops 2 inches in one neighborhood and 0.3 inches a mile away gets captured accurately only if there are observers in both locations. That's what CoCoRaHS does — it creates a dense, accurate precipitation map that no government network can match.
How CoCoRaHS Works
- Sign up free at cocorahs.org. Create an account, enter your location, and get assigned a station ID.
- Mount your Stratus gauge. The Stratus is the official CoCoRaHS gauge — it meets the network's accuracy standards. Mount in an open area per CoCoRaHS guidelines (10+ feet from obstructions, 1–3 feet above ground).
- Check daily. Read your gauge every morning, ideally between 7–9am local time. Record the 24-hour precipitation total.
- Submit your reading online. Log in to cocorahs.org or use the CoCoRaHS app and enter your reading. Takes 60 seconds.
- Your data goes live immediately. Your reading appears on the CoCoRaHS map and is available to NOAA, the National Weather Service, and anyone who uses the network's data.
Who Uses CoCoRaHS Data?
- NOAA and the National Weather Service — for precipitation analysis, flood forecasting, and climate records
- Local farmers and agricultural extension offices — for irrigation scheduling and crop management
- Water utilities — for reservoir management and drought monitoring
- Emergency managers — for flood risk assessment during heavy rain events
- Researchers and universities — for climate and hydrology studies
- Home gardeners — the CoCoRaHS map shows what fell in your neighborhood, not just at the airport weather station miles away
Why the Stratus Gauge is the CoCoRaHS Standard
CoCoRaHS chose the Stratus gauge as their official instrument because it meets their accuracy requirements: 4-inch wide-mouth opening for reliable collection, 0.01-inch precision for meaningful measurement of light events, and consistent performance across all weather conditions. When you submit a CoCoRaHS reading taken with a Stratus gauge, the network knows the data is reliable.
CoCoRaHS + Stratus + Tomato Crater: The Complete Garden Weather System
For serious gardeners, the combination is powerful: Stratus tracks exactly what fell, CoCoRaHS gives you context (what fell in your neighborhood vs. the official weather station), and Tomato Crater delivers precisely what the roots need based on that data. You're no longer guessing at any point in the water cycle — from sky to root zone.
FAQs
What is CoCoRaHS?
CoCoRaHS (Community Collaborative Rain, Hail and Snow Network) is a free volunteer weather observation network where home observers submit daily precipitation readings to NOAA. The network has over 20,000 active observers across the US and fills in precipitation data gaps between official weather stations.
How do I join CoCoRaHS?
Sign up free at cocorahs.org. You'll need a Stratus Precision Rain Gauge (the official CoCoRaHS gauge), a mounting location that meets the network's guidelines, and about 2 minutes per day to check and submit your reading.
Is CoCoRaHS free?
Yes. CoCoRaHS membership is completely free. The only cost is the Stratus gauge itself, which is the official network gauge and costs approximately $20.
How much time does CoCoRaHS participation take?
About 2 minutes per day — check the gauge, read the measurement, submit it online or via the app. Tom does it every morning as part of his garden routine.
Why is the Stratus gauge the CoCoRaHS standard?
The Stratus meets CoCoRaHS accuracy requirements: 4-inch wide-mouth opening, 0.01-inch precision, and consistent performance across all weather conditions. It is NOAA endorsed and the only consumer gauge that meets the network's data quality standards.
More Stratus Resources: Stratus Rain Gauge Hub | Shop Stratus Rain Gauge | Shop Tomato Crater | Learn From Tom
