The US Daily Weather Maps Project provides a free digital archive of United States weather maps published daily between 1871 and 2002. Funding for this project was provided by the National Oceanic and Atmospheric Administration's (NOAA) Climate Database Modernization Program.
One prerequisite to viewing these weather maps is to download and install a browser plug‐in for DjVu (pronounced as déjà vu) files. Similar to Adobe's Acrobat Reader, a DjVu plug‐in allows users to view, zoom, pan and print image files such as these maps. The Project web site includes a link to Caminova's free DjVu plug‐in for Windows and Mac OS computers, though free plug‐ins are also available from other sources.
Daily weather maps from 1871‐1968 are accessible using one of two date selection forms on the Project web site. The earliest maps chronicle the air temperature, barometric pressure, wind velocity and direction, and cloud cover at a small number of reporting stations, as compiled by the US Army Signal Corps. By the time the US Weather Bureau is established in the 1890s, daily weather maps include far more reporting stations, particularly across the Great Plains and Mountain West. In addition, these maps begin to incorporate regional forecasts and data tables noting pressure and temperature changes, maximum/minimum temperatures and precipitation amounts.
In 1968, the Weather Bureau began publishing a weekly compilation of daily weather maps under the title of Daily Weather Maps (Weekly Series). Each week's issue from April 15, 1968 through 2002 provides seven days of maps and is accessible through a second date selection form on the Project website. Weather maps and station observations published after January 1, 2003 are available at a different NOAA web site: www.hpc.ncep.noaa.gov/dailywxmap/
Beyond the raw statistical data and title changes, these maps provide a fascinating look at the evolution of meteorology as a science. The movement of cold and warm air masses, compared with advancing armies and depicted as “fronts”, does not appear on US weather maps until the Second World War. With the advent of high altitude flight and improved weather instruments, upper‐level wind flows are added to weather maps during the mid‐1950s. Also of interest are the observations and forecasts issued prior to and during significant weather events, such as the 1900 Galveston Hurricane or the Tri‐State Tornado of 1925. Those searching for supplemental accounts and analysis of weather map data should also consider searching the archives of Monthly Weather Review, much of which is freely accessible online.
It is worth noting that the scale and data from these weather maps are limited to the 48 contiguous states; Alaska and Hawaii are not included. E‐mail and telephone contact information is posted on the Project website, if users have questions or comments regarding this site.
The US Daily Weather Maps Project is freely accessible and recommended for all public and academic libraries.
