How Much Rain Did You Get?

September 25, 2019

People always are asking how much rain or snow you got at your location. If you like keeping track of precipitation, why not make it part of a vital information resource? The following information comes from the National Weather Service.

The Community Collaborative Rain, Hail and Snow (CoCoRaHS) project is a unique, non-profit, community-based network of volunteers of all ages and backgrounds working together to measure and map precipitation (rain, hail and snow). You can help fill gaps in the rainfall data by becoming a volunteer and taking measurements of precipitation from your location.

Everyone can help, young, old, and the in-between. The only requirements are an enthusiasm for watching and reporting weather conditions and a desire to learn more about how weather can affect and impact our lives.

standard 4" rain gauge from CoCoRaHS

The program helps meteorologists, hydrologists, and researchers study the variability of precipitation and the accumulated data will be available to anyone with a use or interest in precipitation data. The data collected by CoCoRaHS also supports the weather forecasting and warning responsibilities of the NWS.

As the case with all types of data collection, accuracy and consistency are the keys to ensure the observations are meaningful. With that, there are certain types of rain gauges that should be used. The most common, called a 4" rain gauge , makes reading accurate rainfall amounts easy. The funnel collects up to one inch in the rain in the measuring tube with amounts greater than one inch spilling into the overflow tube. Visit CoCoRaHS for more info on this gauge.

It goes back to the consistency aspect of collecting data. Not all rain gauges are created equal nor do they all report the same. The majority of automated rain gauges, when summed over several months or years, report less precipitation than actually fell, and sometimes by a significant amount -- sometimes 25% or more. Also, most automatic gauges cannot collect snow.

CoCoRaHS provides instruction on how and where to set up your equipment as well as how to read and report your observations. You will also be able to see a map of CoCoRaHS observations for your region in "real time."

If you like keeping track of rain and snow events, and would like to share your recordings, you are encouraged to attend a 90 minute CoCoRaHS training The training will be held on October 10 at the Illinois Extension office in Winchester, IL, 401 North Walnut, starting at 6 pm.

Retired Midwest climatologist Steve Hilberg will talk about the Community Collaborative Rain Hail and Snow (CoCoRaHS) program, and how to report precipitation at a specific location. There is no cost to attend. Master Gardeners and Master Naturalists can receive continuing education hours.