When are U.S. Rivers Wet or Dry?

When are U.S. rivers wet or dry? This circular area chart displays the total flow rate in million cubic feet per second throughout a year. Total flow is derived from 1,865 USGS NWIS gages with near complete data for 1951-2020. The amount of flow in rivers in the continental United States varies throughout the year and across the country, but overall where we have gages we see that late winter/early spring months (March - May) tend to have the highest flows and late summer/early fall months tend to have the lowest flows. Extreme events can occur within these long-term ranges, but can also stray outside of them: for example extreme low flows in November 1952 or extreme high flows in June 1972