water year

Any 12-month period, usually selected to begin and end during a relatively dry season, used as a basis for processing streamflow and other hydrologic data; the period from October 1 to September 30 is most widely used in the United States.

Related terms:

• farmer’s year
• grower’s year
• budget year
• one-year ice
• International Geophysical Year
• second-year ice
• two-year ice
• International Polar Year
• One year after Haitian earthquake