Yellowstone River flow by month

From the full USGS record · Livingston 1897-2026

Whether a flow is high or low on the Yellowstone depends almost entirely on the time of year. The same number can be well below normal in July and above normal in October.

Typical flow for each month

The median day for each month across the whole record. The middle column is the range half of all years fall inside. Livingston reads the river below Paradise Valley; Corwin Springs, near Gardiner, reads it above.

Month	Livingston	Middle half	Corwin Springs
January	1,200	1,050–1,370	830
February	1,190	1,030–1,350	814
March	1,280	1,150–1,420	909
April	1,730	1,460–2,170	1,300
May	6,450	4,460–9,410	5,780
June	12,550	9,900–16,900	10,800
July	6,830	4,830–9,090	6,240
August	3,240	2,530–4,140	2,840
September	2,230	1,865–2,700	1,800
October	1,920	1,670–2,330	1,410
November	1,635	1,465–1,870	1,145
December	1,360	1,190–1,510	938

Discharge in cubic feet per second. USGS gauges 06192500 (1897-2026) and 06191500 (1889-2026).

Is this flow high or low?

Where a flow at Livingston falls against every year on record, for the middle of each month from spring to late autumn.

Time of year	1,500 cfs	3,000 cfs	6,000 cfs	12,000 cfs
Mid-Apr	normal	much above normal	much above normal	much above normal
Mid-May	much below normal	below normal	normal	much above normal
Mid-Jun	much below normal	much below normal	much below normal	normal
Mid-Jul	much below normal	much below normal	normal	much above normal
Mid-Aug	much below normal	normal	much above normal	much above normal
Mid-Sep	much below normal	above normal	much above normal	much above normal
Mid-Oct	much below normal	much above normal	much above normal	much above normal
Mid-Nov	normal	much above normal	much above normal	much above normal

So 3,000 cfs is well below normal at the height of runoff and above normal once the river drops in autumn. Every float page shows today’s flow against the record for today’s date.

How flow changes float time

More water moves faster, but speed rises much more slowly than flow: doubling the cfs does not halve the trip. Mallard's Rest to Carter's Bridge, 10.4 river miles, at continuous drift:

Flow	Float time
1,500 cfs	3h 53m
3,000 cfs	2h 59m
6,000 cfs	2h 17m
12,000 cfs	1h 46m

The Mallard's Rest to Carter's Bridge page shows its typical float time for every month, and every stretch in the float index has the same table. How the estimate is made.