Welcome To CoCoRaHS


Welcome to CoCoRaHS


Welcome to CoCoRaHS – the “Community Collaborative Rain, Hail and Snow Network”.  We are a group of nearly 20,000 volunteers measuring precipitation in our own neighborhoods, but collectively tracking storms across the whole country.  Thanks for joining the observing team.  We hope this will be an educational and fun activity.  Here is some information to help you get started.


Do not put your personal safety or health at risk to read your gauge.  Remember, weather at times can be unpredictable.  Use the same precautions when reading your gauge as you would with any other outside activity.  A CoCoRaHS volunteer with experience in Occupational Heath and Safety wrote the following safety document: CoCoRaHS Observer Safety Tips.


If you filled out the application on the www.cocorahs.org web site and provided an e-mail address, an e-mail was sent directly to the address you provided.  This message contained your default username and password.  After typing in this information, click the "Save Login" checkbox, and you will not have to log in again from that computer.  Most browsers provide functions to remember your login information, and this is recommended.  If you did not receive the initial e-mail with your login info, your e-mail system may have blocked it, or your application contained a typo in the e-mail address.  You may need to e-mail info@cocorahs.org to confirm that we received your application and that we have your correct e-mail.

If you forget your username or password you can have them e-mailed to you at any time by using the "Find Login Information" form at www.cocorahs.org/FindLoginInfo.aspx.


When your station is established we locate it on maps using the address or coordinates provided in your application.

Your station name is determined by your distance and direction, as-the-crow-flies, from the geographical center of the town indicated by your station name.  The geographical center of the town is normally where maps place the city name.  For example, the name Fort Collins 3.3 SE, indicates that the gauge is located 3.3 miles southeast of the approximate center of Fort Collins. 

We sometimes make mistakes so PLEASE CHECK YOUR STATION NAME.  If the name does not reasonably describe your location, please email us (info@cocorahs.org).  You can also click on the link to Google Maps in your CoCoRaHS account information to view your station location.

Once you have logged into your CoCoRaHS account, the server will automatically fill in your station name on your data entry form each day.

Your STATION NUMBER is based on the state and county in which you live.  Each station has a unique station number that is automatically assigned.



All volunteers are required to use the same type of manual rain gauge (4" diameter, high capacity) so that our data are consistent and compatible. CoCoRaHS vendors who provide reduced rates for CoCoRaHS volunteers include: WeatherYourWay and additional suppliers.  The basic gauge should cost around $42 plus shipping. They are usually shipped out right away so you can set up your gauge in a matter of days.

**Please note: The "Outback Blue" rain gauge (with a black-colored funnel) for sale on Amazon and other web sites is NOT approved for CoCoRaHS use.  Click here to learn more, and what to do if you already bought one.** Please reach out to info@cocorahs.org if you have questions.

In some states, sponsors may provide approved rain gauges at little or no cost to volunteers in special cases.  Please check with your local or state coordinators to see if complimentary sponsored gauges are available in your county and state.  The cost of a gauge should not stop you from joining.

Click here to read about why CoCoRaHS doesn't allow automated gauges.



The best way to get started in CoCoRaHS is to attend a training session for new volunteers.  Check with your local coordinator about dates and locations. Your local coordinator's name and e-mail address can be found in the "cc" box in the header of your welcome e-mail, or look up your local and state CoCoRaHS coordinators here.

You may also train on-line on the CoCoRaHS website.  Click on "Training Slide Shows" to access training material as well as view our animated training materials via our YouTube page.   In areas that experience snow, or if you are just mildly interested, we also highly recommend you view the pages on measuring snowfall: http://www.cocorahs.org/Content.aspx?page=measuresnow.  Additional information is contained with "Things to know about Rain, Hail and Snow" and even more under "FAQ/Help".  Ultimately, we recommend attending a training session if it is offered in your area because you can ask questions and enjoy the company of others interested in weather watching.         

If you have attended a CoCoRaHS training session or trained on-line, and you have your rain gauge and snowboard (when applicable) in place, you can begin reporting immediately.



The most common way to report your daily precipitation totals as well as special hail and intense precipitation reports is on our website: www.cocorahs.org .  To report your precipitation measurements click on "My Data".  Feel free to fill in the "Observation Notes" section with any additional information that will help describe your observation and the weather you experienced.

If you have an iPhone or Android based smart phone, you can report daily observations via the CoCoRaHS observer app. 

The CoCoRaHS iPhone App is available at the Apple Store: https://itunes.apple.com/us/app/cocorahs-observer/id827714558?mt=8

The CoCoRaHS Android App can be downloaded via the Google Play Store: https://play.google.com/store/apps/details?id=com.appcay.cocorahs


We have selected 7:00 a.m. as the preferred time for daily observations since it is most convenient for the majority of volunteers and a time when it is less likely to be raining or snowing.  For mapping precipitation and comparing data among stations, it is helpful to all measure at about the same time.

If your schedule does not permit you to check your gauge at 7:00 a.m., please make sure you type in the actual time you took your observation on the data entry form.  Observations made before 4:30 a.m. or after 9:30 a.m. will not appear on the daily maps.       

If it is raining or snowing at or near your observation time, it is important for you to report exactly when you read and emptied your gauge so we can interpret the data properly.  If it is not raining or snowing, reporting the exact reading time is not critical.         

We realize that you may not have time to report your observations to us exactly at 7:00 a.m.  The sooner you can report, the better, but report whenever you are able.  You can go back at any time to report data from past weeks, months, and even years.  Please make sure you enter the date of observation correctly when you enter data from the past.


We greatly appreciate daily reports covering consistent 24-hour periods when possible, even when there has been no precipitation (report 0.00") or just a trace (report "T").  For many reasons, including drought monitoring, it is just as important to know that it didn't rain at your location, as well as when it did!        

If you are away from home for a period of time, enjoy yourself and don't worry about CoCoRaHS. You may ask a friend or neighbor to read your gauge for you or report the total precipitation in the gauge when you get back.  Little rain evaporates from the gauge as long as the funnel is left in place.  Do not let water freeze in the inner tube or it will crack.

To report rainfall while you were away, use the "MULTI-DAY ACCUMULATION FORM".  When you return, follow the instructions on how to enter an accumulated rainfall amount for a period of multiple days.



If you observe hail, submit an on-line "HAIL REPORT" after each storm. This information is really helpful even if the hail is small, soft, or not comprised of many stones.  If you were not at home and do not know the exact time of the storm, please submit a hail report with any observations you have, even if approximate.

If you experience heavy rain or other significant weather in progress, please submit a "SIGNIFICANT WEATHERREPORT."  Use this same form to report heavy snow in the winter.  The definition of “heavy rain” varies with climate regions across the country, but rainfall of at least 0.30” per hour should be reported.  If rainfall exceeds 1-2 inches per hour, your timely report may be extremely important as flooding conditions may be developing rapidly.

All hail and significant weather reports are automatically transmitted to the National Weather Service Forecast Office. Your information may be critical to alert forecasters of threatening weather.

If your state participates in the "hail pad" portion of the program.  Please see our web site for hail pad pick-up and collection sites .

You are welcome to make your own hail pads or you can purchase one at weatheryour way.com. Even if you do not have a hail pad, please report hail when it is falling in your backyard.



After you begin reporting data to CoCoRaHS, please refer to the "MAPS" section on our web site for your city and county.  Make sure your data are appearing, and showing up in the correct location.  If not, please let us know immediately.  When you submit your report, it may take a few minutes before it appears on the maps.

Also, you can check reports by clicking on "LIST/EDIT MY REPORTS" under the "MY DATA" section, or by clicking "VIEW DATA" near the top of the page.  Always make sure your data are typed correctly and entered on the right date.  If you make a mistake with a daily entry, click on the pencil to the right of the report and resubmit the corrected entry.  Many may look at and use your data and these data will be archived indefinitely.

All maps, both recent and historic, are posted on our web site.  As you examine them, you will begin to learn along with us how precipitation patterns vary in our states. You can review all the data reports you have submitted, or you can check the rainfall totals for all stations in your county—and more.  Just experiment!



CoCoRaHS volunteers check data from all volunteers on a regular basis to spot errors.  Don't be concerned if you get a message asking you to check one of your reports.  We rely on e-mail to keep you posted, so don't let your SPAM filter block us out.  We just want to make sure the data are as accurate as possible.  If you notice an error on the map and want to let us know about it (especially if it is more than a few days old), you can send an e-mail to qc@cocorahs.org.  



During the warm weather, you may leave your gauge outside.  During cold weather, when the temperatures drop below freezing, the funnel and inner calibrated tube should be kept indoors.  During cold weather, it is usually best to bring the entire gauge inside if you are gone for more than two or three days.  If left outside, a cycle of melting and freezing precipitation may crack your gauge.

We have found that our gauges begin to get brittle over time.  With reasonable care, you should get 5-20 years of use out of the gauge.  If you want your gauge to look new for a long time, wrap the outside with a thin coat of foil or other material to reflect ultraviolet radiation.  Avoid putting anything inside the funnel, as that could affect the accuracy of your data.  We've been told that some automotive care products applied to the outside of the gauge may add to the life of the gauge, but they may make it slippery to hold.

If you want to keep your gauge clean and looking like new, put some warm water with a little gentle liquid hand soap in the tube and let it soak for a few minutes. Then twist a thin soft towel and spin it into the cylinder until it reaches the bottom. This will wipe out most of the dirt. It is not recommended to use a firm bottlebrush to clean the gauge, nor is using your automatic dishwasher (this will gradually scuff and haze the inside of the gauge).

Another method is to take a newspaper, roll it to make a tight cylinder, and then rotate the paper on the inside of the tube all the way to the bottom. It will usually clean out the dirt.


Your name will be added to our CoCoRaHS e-mail list, and periodically you will receive project updates and reminders.  We try to limit our messages to about two per month.  Should your e-mail address or mailing address change, please let us know so we don't lose contact with you. If you do not want to be on our e-mail list, just let us know. You will also want to make sure that our messages are not blocked by your e-mail's SPAM filter.

Check our web pages for periodic updates.  We use our web site to keep volunteers informed of our progress and upcoming activities.  We also provide links to interesting weather and climate websites and educational resources.


Are you a social media person?  If so you can follow CoCoRaHS via Facebook and Twitter.  The CoCoRaHS Blog is another spot where you can find out great information about weather and climate while leaving comments and questions for discussion.


The CoCoRaHS network was created as a result of the Fort Collins, Colorado flash flood of July 28, 1997, and the storm the following evening on Pawnee Creek, near Sterling, Colorado. Both storms produced more than 12 inches of rain in a short period of time, but over very small areas.  In Fort Collins, several areas within five miles of the storm center received just two inches of rain or less.  The flood claimed several lives.  The Colorado Climate Center was responsible for documenting those storms.  It took months of work to piece together the puzzle.  Without reports from private citizens with rain gauges, we would not have been able to map and study those storms. 

In 1998, the network gained the support of organizations that benefit from detailed local weather data.  Then in 2003, a National Science Foundation Grant helped us expand beyond the Fort Collins area.  This was followed by a NOAA's Environmental Literacy Program Grant in 2006 which allowed us to expand to all fifty states. In 2010 we were awarded grants from both the National Science Foundation and the NOAA Office of Education.  With the help of these sponsors, as well as financial donations from other organizations and individuals, we have been able to continue to keep CoCoRaHS operational and will continue to make improvements to make the network a more fulfilling experience.

For many years we have recognized a need for more detailed local weather data to document our climate patterns and water resources. CoCoRaHS is now making this a reality.

In 1998, Colorado became the first state to join the network. Nationwide, there are thousands of citizens of all ages (from kids in kindergarten to folks in their 80s and 90s) active in CoCoRaHS. Today, all fifty states, all provinces of Canada, Puerto Rico, The Bahamas and the U.S. Virgin Islands are all participating in CoCoRaHS, providing a wealth of precipitation data not previously available!



CoCoRaHS is a low-tech, low-cost but highly effective approach to a challenging problem.  Precipitation is very important and highly variable.  Weather stations in existing official weather observing networks are just too far apart.  Automated weather stations are useful, but too expensive and not always accurate.  By encouraging as many volunteer weather watchers as possible, CoCoRaHS provides local information on rain, hail, and snow that helps fill the gaps between traditional weather stations, thereby providing valuable information for forecasting, research, and education.

As CoCoRaHS continues to grow across the country we realize that our volunteers are our best resource for recruiting new participants.  If you know of others who may want to join CoCoRaHS, please encourage them to apply.  Our hope is to have a dense network of active CoCoRaHS volunteers everywhere.



Data collected each day by CoCoRaHS volunteers are used by many professionals across the country weather forecasters, hydrologists, in water management, by researchers, in agriculture, by climatologists, in the insurance industry, engineering, recreation and many others.  Who Uses CoCoRaHS Observations

Some examples of how your data reports are used include:

  • flood and river level forecasts and verification
  • drought severity and impact assessment
  • weather forecast verification
  • providing “ground truth” for many weather radar and satellite products
  • assessing crop conditions and predicting crop yields
  • storm damage reports
  • water supply and water demand forecasts for municipalities
  • climate descriptions and monitoring
  • transportation and recreation
  • research and education 

    Here are some examples of the important questions being answered using CoCoRaHS precipitation reports:

  • What is the distribution of precipitation across the country each day?
  • How do precipitation patterns change seasonally and geographically across the country?
  • How much of the annual precipitation falls as snow versus rain?
  • How much water content is in the snow and how does water content vary?
  • How many days per month, season, and year does precipitation fall—at each point, over an entire county, over a state, over the whole country?How much does that vary from one year to the next?
  • How much rain is needed to produce local or widespread flooding?
  • In situations of heavy rain, are the cores of heavy precipitation widespread or very localized?
  • Is the frequency and extent of heavy rainfall (or snowfall) changing over time?
  • How do precipitation patterns affect crop production, rangeland, wildfire potential, fish, animal, bird and insect populations, etc.?
  • Can we improve our forecasts of water supply and water demand by knowing local rain and snow patterns better?
  • How many hailstorms occur each year and what are their characteristics?
  • How accurately do meteorological radar systems track storms and estimate rainfall amounts?

These are just a few of the questions that you will be helping answer.  It will take time before we have good answers to all these questions.  Each season we are learning more and more.  Your data will help in many ways.







Nolan Doesken, our National Director, is the former state climatologist for Colorado.  He is based at Colorado State University and is the founder of the Community Collaborative Rain, Hail and Snow Network (CoCoRaHS). Nolan has been monitoring Colorado's climate since 1977.  In addition to other duties, Nolan also assists in the operation of the Fort Collins, Colorado National Weather Service Cooperative Weather Station on the Colorado State University campus.  This historic weather station has been operated continuously since the 1880s. email: nolan@atmos.colostate.edu

Henry Regesour National Coordinator, is a meteorologist at Colorado State University.  Henry joined the CoCoRaHS team in 2004 after working many years with the American Meteorological Society in Boston.  His background includes fire weather in Alaska and time with the National Climatic Data Center (NCDC) in Asheville, NC.  In addition to meteorology, he also holds degrees in business and economics. A close call with lightning when he was eight "sparked" his interested in weather. Henry enjoys photography, gardening, running, cooking, and puns.  email: henry.reges@colostate.edu

Julian Turner, our Web Developer has been building websites since graduating from the University of Colorado at Boulder with degrees in Environmental Sciences and Economics in 1999. He earned a Master of Computer Information Systems degree from Colorado State University in 2019. Julian has been a vital part of the CoCoRaHS team since 2003. email: julian.turner@colostate.edu


Noah Newman, our Education Coordinator has a passion to help educate the nation about precipitation.  Noah joined CoCoRaHS in 2009 after working with the GLOBE program for several years.  Noah enjoys winter sports, astronomy, white water rafting and political science.  He has three cats, Potchky, Pupik and Mishigoss. email: noah.newman@colostate.edu


Steve Hilberg, our Project Manager has a special interest in data quality assurance and quality control. He has been associated with CoCoRaHS as Illinois State Coordinator since late 2006. He joined the CoCoRaHS staff in 2019. His background is in meteorology and climatology, and retired as director of the Midwestern Regional Climate Center in 2011. His weather interests are in winter weather and snow, and a co-developer of the Accumulated winter Season Severity Index (AWSSI). Steve enjoys woodworking, cooking, and fishing in his spare time. email: hberg@cocorahs.org

Dani Talmadge, our QC Specialist is a meteorologist at Colorado State University.  Dani joined the CoCoRaHS team in 2014 after serving as a Weather Forecaster in the United States Air Force.  In addition to meteorology, she also holds degrees in weather technology and computer programming. Dani enjoys photography, knitting, hiking with her dog Copper, and hail pad analysis! email: dani.talmadge@colostate.edu

Carol Stolz, our Help Desk Coordinator is a retired high-school science teacher, specializing in the Earth Sciences.   Besides answering CoCoRaHS help desk requests, Carol also submits reports for those observers who call-in their data.   She has been an observer for the CoCoRaHS Network since 2005.  Carol and her husband enjoy camping and hiking with their dog, Ellie.   Carol also enjoys “keeping her eye to the sky”, watching the clouds for those special and significant weather events! 
email: carol@cocorahs.org

If you have any questions, please do not hesitate to contact us by e-mail: info@cocorahs.org.