Rivermatics

USGS Streamgage 06186500

Yellowstone River at Yellowstone Lake Outlet YNP

Yellowstone River at Yellowstone Lake Outlet YNP is USGS streamgage 06186500 in Wyoming, monitoring river discharge in hydrologic subbasin 10070001. It sits on the Yellowstone River, alongside 9 other gauges Rivermatics tracks on the same river. It drains a watershed of about 995 square miles. Discharge records at this site go back to 1923. Typical flow runs near 3,802.6 cfs in July and 544.1 cfs in April, with the higher of the two arriving in July. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.

View live conditions & forecast →

Gauge details

State
Wyoming
Drainage area
995 sq mi
Gauge elevation
7,736 ft
Subbasin (HUC-8)
10070001
Coordinates
44.56709, -110.38041
USGS site number
06186500
Records begin
1923-07-06 (103 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Yellowstone River at Yellowstone Lake Outlet YNP. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
840 889 920
819 879 913
795 862 901
783 851 895
769 837 881
755 825 872
749 825 881
742 815 870
728 805 864
719 795 858
707 786 853
697 779 850
685 770 846
675 762 842

All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 100 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 223.5 375.6 580.9
February 206.6 387.7 569.6
March 266 452.5 609.8
April 409 544.1 714.2
May 697.3 1,130.4 1,885.3
June 2,269.7 3,587.3 5,640.7
July 2,234.2 3,802.6 6,014.5
August 1,194.7 2,048.7 3,110
September 733.7 1,114.2 1,697.7
October 533.5 744.9 1,095.5
November 400.2 594.7 807
December 292.9 463 650.9

All values in cubic feet per second (cfs).

Common questions

When does Yellowstone River at Yellowstone Lake Outlet YNP normally run highest?
July, on the long-term record. The median daily flow that month is about 3,802.6 cfs, against 375.6 cfs in January, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Yellowstone River at Yellowstone Lake Outlet YNP?
It depends on the month. In January, half of days historically fall near 375.6 cfs, with the middle 80% of days between 223.5 and 580.9 cfs. The month-by-month table on this page gives the full range.
How long has Yellowstone River at Yellowstone Lake Outlet YNP been measured?
Discharge records at USGS site 06186500 begin in 1923, about 103 years, covering roughly 9,200 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Yellowstone River at Yellowstone Lake Outlet YNP?
Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on the live gauge screen. Open live conditions to see the current outlook.
Where is Yellowstone River at Yellowstone Lake Outlet YNP?
The gauge sits at 44.56709, -110.38041, in Wyoming, in hydrologic subbasin 10070001, at an elevation of about 7,736 feet, draining roughly 995 square miles.
Can I use Yellowstone River at Yellowstone Lake Outlet YNP data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Upstream and downstream on the Yellowstone River

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Yellowstone River in full.

Other gauges in this subbasin