Rivermatics

USGS Streamgage 12181000

Skagit River at Marblemount, WA

Skagit River at Marblemount, WA is USGS streamgage 12181000 in Washington, monitoring river discharge in hydrologic subbasin 17110005. It sits on the Skagit River, alongside 11 other gauges Rivermatics tracks on the same river. It drains a watershed of about 1,381 square miles. Discharge records at this site go back to 1943. Typical flow runs near 6,538.4 cfs in July and 5,381.3 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, alongside daily high and low water-temperature forecasts.

View live conditions & forecast →

Gauge details

State
Washington
Drainage area
1,381 sq mi
Gauge elevation
313 ft
Subbasin (HUC-8)
17110005
Coordinates
48.53373, -121.42985
USGS site number
12181000
Records begin
1943-09-01 (83 years)
Rivermatics forecast
14-day flow outlook + water temperature

14-day flow forecast

Based on observations through for Skagit River at Marblemount, WA. 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
3,959 4,258 4,482
3,739 4,252 4,592
3,549 4,278 4,803
3,481 4,282 4,906
3,346 4,275 5,023
3,257 4,258 5,097
3,218 4,265 5,255
3,162 4,248 5,308
3,059 4,209 5,364
2,985 4,208 5,499
2,938 4,184 5,503
2,842 4,121 5,476
2,763 4,050 5,419
2,750 4,058 5,491

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 83 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 3,880.6 6,849.4 9,504.5
February 3,383.4 6,914.5 9,490.7
March 3,487.1 5,935.8 8,474.8
April 3,676.3 5,381.3 7,665.7
May 3,978.7 6,014.5 9,551.3
June 4,036.7 6,911.3 11,644.3
July 3,506.8 6,538.4 12,292.9
August 2,708.4 4,078.1 6,745.2
September 2,700.3 3,834.3 5,375
October 2,431.3 4,182.9 7,416.8
November 3,504.3 5,653 12,432.3
December 3,732.9 5,504.8 9,858.1

All values in cubic feet per second (cfs).

Common questions

When does Skagit River at Marblemount, WA normally run highest?
February, on the long-term record. The median daily flow that month is about 6,914.5 cfs, against 3,834.3 cfs in September, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Skagit River at Marblemount, WA?
It depends on the month. In January, half of days historically fall near 6,849.4 cfs, with the middle 80% of days between 3,880.6 and 9,504.5 cfs. The month-by-month table on this page gives the full range.
How long has Skagit River at Marblemount, WA been measured?
Discharge records at USGS site 12181000 begin in 1943, about 83 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 Skagit River at Marblemount, WA?
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. A companion model forecasts each day's water-temperature high and low. 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 Skagit River at Marblemount, WA?
The gauge sits at 48.53373, -121.42985, in Washington, in hydrologic subbasin 17110005, at an elevation of about 313 feet, draining roughly 1,381 square miles.
Can I use Skagit River at Marblemount, WA 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 Skagit River

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

Other gauges in this subbasin