USGS Streamgage 12150800
Snohomish River near Monroe, WA
Snohomish River near Monroe, WA is USGS streamgage 12150800 in Washington, monitoring river discharge in hydrologic subbasin 17110011. It sits on the Snohomish River, alongside 1 other gauge Rivermatics tracks on the same river. It drains a watershed of about 1,537 square miles. Discharge records at this site go back to 1963. Typical flow runs near 4,907.4 cfs in July and 9,443 cfs in April, with the higher of the two arriving in April. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.
View live conditions & forecast →
Gauge details
- State
- Washington
- Drainage area
- 1,537 sq mi
- Gauge elevation
- 16 ft
- Subbasin (HUC-8)
- 17110011
- Coordinates
- 47.83093, -122.04846
- USGS site number
- 12150800
- Records begin
- 1963-02-01 (63 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Snohomish River near Monroe, 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.
| Date | Low p10 | Expected p50 | High p90 | Range |
|---|---|---|---|---|
| 1,238 | 1,282 | 1,325 | ||
| 1,218 | 1,271 | 1,328 | ||
| 1,294 | 1,442 | 1,937 | ||
| 1,388 | 1,761 | 2,967 | ||
| 1,374 | 1,719 | 2,688 | ||
| 1,354 | 1,605 | 2,234 | ||
| 1,291 | 1,494 | 1,972 | ||
| 1,250 | 1,430 | 1,830 | ||
| 1,224 | 1,389 | 1,726 | ||
| 1,192 | 1,347 | 1,644 | ||
| 1,175 | 1,324 | 1,598 | ||
| 1,152 | 1,300 | 1,558 | ||
| 1,131 | 1,279 | 1,522 | ||
| 1,118 | 1,267 | 1,521 |
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 64 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| January | 4,613.2 | 9,756.5 | 27,335.5 | |
| February | 4,421.7 | 8,140.3 | 21,272.4 | |
| March | 4,638.4 | 8,055.5 | 17,409.7 | |
| April | 5,991.7 | 9,443 | 16,853.3 | |
| May | 7,652.6 | 11,974.2 | 20,496.8 | |
| June | 5,833 | 10,857.3 | 20,063.3 | |
| July | 2,806.8 | 4,907.4 | 12,186.1 | |
| August | 1,579.4 | 2,268.4 | 5,302.6 | |
| September | 1,344.7 | 2,192.3 | 6,093.3 | |
| October | 1,705.5 | 4,334.5 | 13,969 | |
| November | 3,983.7 | 9,779 | 27,150 | |
| December | 4,605.5 | 9,561 | 26,558.1 |
All values in cubic feet per second (cfs).
Common questions
- When does Snohomish River near Monroe, WA normally run highest?
- May, on the long-term record. The median daily flow that month is about 11,974.2 cfs, against 2,192.3 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 Snohomish River near Monroe, WA?
- It depends on the month. In January, half of days historically fall near 9,756.5 cfs, with the middle 80% of days between 4,613.2 and 27,335.5 cfs. The month-by-month table on this page gives the full range.
- How long has Snohomish River near Monroe, WA been measured?
- Discharge records at USGS site 12150800 begin in 1963, about 63 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 Snohomish River near Monroe, 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. 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 Snohomish River near Monroe, WA?
- The gauge sits at 47.83093, -122.04846, in Washington, in hydrologic subbasin 17110011, at an elevation of about 16 feet, draining roughly 1,537 square miles.
- Can I use Snohomish River near Monroe, 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 Snohomish River
Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Snohomish River in full.
- Snohomish River near Monroe, WA this page
- Snohomish River at Snohomish, WA 1,714 sq mi