National Weather Service United States Department of Commerce

On September 1st, the Office of the Delaware State Climatologist will kickoff an effort to enlist community volunteers to measure and map rain and snow across the First State. The effort is part of a growing national network of home-based weather buffs known as the Community Collaborative Rain, Hail and Snow Network or CoCoRaHS. CoCoRaHS was launched in Colorado over 10 years ago, and since then many other states have joined, with over 12,000 volunteer observers nationwide. Delaware CoCoRAHS is looking for volunteers to take rain and snow measurements. To join, go to the following website and sign up:

CoCoRAHS observers take daily measurements of precipitation from a set location. These measurements are reported on the CoCoRaHS website by the observer. The data are then displayed and organized and may be accessed by any individual user or organization. All that is needed to participate is an official CoCoRAHS 4" rain gauge (which costs $23 + shipping and can be purchased through several vendors on the CoCoRAHS website), an internet connection, and a yardstick to measure snow depth. Training is provided for CoCoRaHS observers, either through online training modules on the CoCoRAHS website, or if needed, in group training sessions at several locations around the state.

We hope you´ll become a Delaware CoCoRAHS observer. If you have any questions or need additional information, please e-mail us at or call us at (302) 831-6906.

An Opportunity to Participate in a NJ Precipitation Observation Network
Dave Robinson and Mat Gerbush
NJ Community Collaborative Rain, Hail and Snow Network Coordinators
Rutgers University

A new precipitation observing network began in New Jersey on Groundhog Day, 2008. Coordinated by the Office of the NJ State Climatologist at Rutgers University's Agricultural Experiment Station, CoCoRaHS (Community Collaborative Rain, Hail, and Snow network) is a community-based precipitation observing network that has rapidly expanded throughout a number of states. You may sign up by going to

CoCoRaHS observers are trained to collect high-quality daily precipitation data. Observations are entered onto a web form via the CoCoRaHS website, archived, and displayed on the site for end users that include meteorologists, hydrologists, farmers, water resource managers, as well as you! The CoCoRaHS website also allows observers to report hail and intense precipitation events, observations that are immediately relayed to the National Weather Service for use in the issuance of warnings.

All that is needed to participate is an internet connection, a 4" diameter plastic precipitation gauge, and a ruler for measuring snow. Training is provided for CoCoRaHS observers, either through online training modules, or preferably, in group training sessions that will be held at several places around NJ over the coming several months.

Please consider becoming a NJ CoCoRaHS observer! You can contact us with any questions at

Air Quality

The National Oceanic and Atmospheric Administration (NOAA), in partnership with the Environmental Protection Agency (EPA), issues daily air quality forecast guidance as part of a national Air Quality Forecasting Capability. NOAA's National Weather Service (NWS) currently provides forecast guidance for ozone and smoke based on numerical atmospheric predictions updated twice daily. read more ...

Air Quality Forecast Guidance
Air Quality Alerts (AQA)
Air Quality Indexes (AQI)
About the Air Quality Index

The EPA developed the Air Quality Index (AQI) which reports levels of ozone, particle pollution, and other common air pollutants on the same scale. An AQI reading of 101 corresponds to a level that is above the national air quality standard - the higher the AQI rating, the greater the health impact. The AQI is divided into color-coded categories, and each category is identified by a simple informative descriptor. The descriptors are intended to convey to the public information about how air quality within each category relates to public health. 

The table below defines the AQI categories.

AQI AQI Category AQI Color Formulas
Numbers (Descriptor) Color (RGB) (CMYK)
0 - 50 Good Green 0,228,0 224,0,224,30
51 - 100 Moderate Yellow 255,255,0 0,0,255,0
101 - 150 Unhealthy for Sensitive Groups Orange 255,126,0 0,132,255,0
151 - 200 Unhealthy Red 255,0,0 0,255,255,0
201 - 300 Very Unhealthy Purple 153,0,76 0,153,80,102
301 - 500 Hazardous Maroon 76,0,38 0,76,38,179
Partner Agencies for Air Quality
in PA, NJ, DE, MD and the Delaware Valley
Air Quality Resources