Weather and climate data are collected and maintained by a variety of organizations for a wide range of purposes. For the most part, archived weather and climate data are available for public use. However, raw precipitation and temperature data can be difficult to find and interpret; this may not be your primary interest. In Arizona, raw climate, weather, and drought data and information are interpreted and presented in a variety of reports.
Below, links are provided to the climate and weather reports and interpretive summaries generated within Arizona. Additionally, links to raw weather and archived climate data are also provided.
Reports and Summaries
A variety of interpretive summaries are produced by climate scientists for the state of Arizona at multiple times throughout the year. These reports offer interpretation of the current and past climate conditions and of forecasts and put the current conditions into an historical context.
Arizona Drought Monitor
The Arizona Drought Monitor Report is a monthly publication produced by the Arizona Governor's Drought Monitoring Technical Committee. This report provides information on short-term and long-term drought status across the state and is intended for use by land managers, policy-makers, and the public.
Southwest Climate Outlook
The Southwest Climate Outlook is a monthly publication of the Climate Assessment for the Southwest (CLIMAS) and the University of Arizona Cooperative Extension that provides information about recent drought and climate conditions in the Southwestern United States, along with forecasts for the coming months. In addition, each issue includes a feature article on relevant topics such as drought, floods, tropical storms, monsoon, and long-term climate patterns.
Southeast and Northwest Arizona Climate Summaries
To address information gaps in the southeast and northwestern portions of Arizona, the University of Arizona Cooperative Extension produces seasonal climate summaries specific to these areas. These reports interpret drought, forecast, and weather information for ready use by land managers and the public.
Raw Data Access
Weather has long interested humans, and records of daily conditions have been kept in many places for centuries. In the United States, weather observations date back to the 1890s in several locations. Daily and sometimes hourly observations of precipitation and temperature are available through several sources. Depending on the source, additional variables including wind speed and direction, relative humidity, and dewpoint may also be available.
National Weather Service
The National Weather Service (NWS) webpage offers a wealth of information, ranging from daily and long-range forecasts to graphical maps of daily and long-term average precipitation and temperature. Weather watch and warning information is also provided at this site.
National Climatic Data Center
The National Climatic Data Center (NCDC) is the world's largest archive of weather data. From this site, you can download a great deal of historical data. Datasets can be explored and downloaded from the "Data & Products" section of the NCDC website. The "Help/FAQ" section of this page guides users through accessing desired data. Data are available across the globe and include Radar imagery, 15 minute and hourly precipitation totals, and hourly, daily, and monthly temperature averages. A fee is associated with some datasets, but many are available free of charge.
Western Regional Climate Center
The Western Regional Climate Center (WRCC) archives and makes available historical climate data and summaries from several different weather observing networks including NWS Cooperative Observer Program (COOP) stations, Remote Automated Weather Stations (RAWS), NWS Automated Surface Observing System stations (ASOS), and NRCS SNOwpack TELemetry (SNOTEL) stations. Each of these networks of weather stations is maintained by a different segment of the federal government in support of different activities. RAWS stations support wildland fire management; SNOTEL stations monitor snowfall to assist in producing water supply forecasts.
A demonstration on the next page will walk you through how to access data on the WRCC site and how to bring it into Excel for further analysis and plotting, if desired.
Arizona State Climatologist's Office
The primary goal of the Arizona State Climatologist's Office is to provide climate information in support of operational, education, planning, and research endeavors within the state. This site provides access to Arizona-specific data and information.
The Arizona Meteorological Network
The Arizona Meteorological Network (AZMET) provides meteorological data and weather-based information to agricultural and horticultural interests operating in southern and central Arizona. Meteorological data is collected from a network of automated weather stations located in both rural and urban production settings to supplement stations maintained by the federal government (NWS COOP, ASOS, etc). Daily and hourly raw data and daily, weekly, and monthly reports can be downloaded directly from this site. In addition to directly measured variables including temperature (air and soil), humidity, solar radiation, wind (speed and direction), and precipitation, AZMET sites offer a variety of computed variables, including heat units (degree-days), chill hours, and reference crop evapotranspiration (ETo).
WorldClimate provides simple long-term monthly temperature and precipitation averages from weather stations around the world. Much of the data presented on this site is the same data served up on the WRCC and NCDC websites, however, averages presented are sometimes calculated for periods other than the 30-year normals used by climatologists.
Next, you will observe how to access and download data from the Western Regional Climate Center website.