The "monthly streamflow" map shows the average streamflow conditions  for the past month.

The map depicts monthly streamflow conditions as computed at USGS streamgages. The colors represent monthly streamflow compared to percentiles of historical monthly streamflow  for the month of the year. This map represents conditions adjusted for this time of the year. Only streamgages having at least 30 years of record are used.

States containing no dots indicate locations where flow data for the current day are temporarily unavailable. During winter months, some states (or parts of states) may have fewer dots than at other times of the year due to ice effects.

The data used to produce this map are provisional and have not been reviewed or edited. They may be subject to significant change.

Alternative data formats of this map in postscript , GIS coverage, or GIS shapefile are available.