USGS Streamgage 06200000
Boulder River at Big Timber, MT
Boulder River at Big Timber, MT is USGS streamgage 06200000 in Montana, monitoring river discharge in hydrologic subbasin 10070002. It drains a watershed of about 525 square miles. Discharge records at this site go back to 1947. Typical flow runs near 996 cfs in July and 191.4 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
- Montana
- Drainage area
- 525 sq mi
- Gauge elevation
- 4,056 ft
- Subbasin (HUC-8)
- 10070002
- Coordinates
- 45.83379, -109.93871
- USGS site number
- 06200000
- Records begin
- 1947-04-01 (79 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for Boulder River at Big Timber, MT. 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 |
|---|---|---|---|---|
| 68.7 | 74.9 | 80.8 | ||
| 66.6 | 73.7 | 80.1 | ||
| 64.2 | 71.7 | 78.4 | ||
| 62.7 | 70.2 | 77.1 | ||
| 61.5 | 69.1 | 76.4 | ||
| 60.5 | 68.6 | 76.9 | ||
| 59.9 | 68.3 | 76.7 | ||
| 58.9 | 67.3 | 75.7 | ||
| 57.7 | 66.4 | 75.3 | ||
| 56.8 | 65.6 | 75.3 | ||
| 56.2 | 65.3 | 76.1 | ||
| 55.4 | 64.9 | 77.3 | ||
| 54.7 | 64.4 | 76.8 | ||
| 53.9 | 63.9 | 76.9 |
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 78 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 | 85.2 | 135.1 | 184.1 | |
| February | 85.1 | 126 | 172.2 | |
| March | 98 | 126.6 | 170.9 | |
| April | 124.6 | 191.4 | 363.7 | |
| May | 439.6 | 1,000.1 | 2,163.5 | |
| June | 1,261.2 | 2,552.3 | 4,653.3 | |
| July | 362.8 | 996 | 2,244 | |
| August | 77.5 | 187.3 | 438 | |
| September | 63.4 | 151.9 | 340.4 | |
| October | 114.7 | 209.3 | 343.7 | |
| November | 129.5 | 191.7 | 270.9 | |
| December | 99 | 156.6 | 211.8 |
All values in cubic feet per second (cfs).
Common questions
- When does Boulder River at Big Timber, MT normally run highest?
- June, on the long-term record. The median daily flow that month is about 2,552.3 cfs, against 126 cfs in February, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Boulder River at Big Timber, MT?
- It depends on the month. In January, half of days historically fall near 135.1 cfs, with the middle 80% of days between 85.2 and 184.1 cfs. The month-by-month table on this page gives the full range.
- How long has Boulder River at Big Timber, MT been measured?
- Discharge records at USGS site 06200000 begin in 1947, about 79 years, covering roughly 9,199 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Is there a flow forecast for Boulder River at Big Timber, MT?
- 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 Boulder River at Big Timber, MT?
- The gauge sits at 45.83379, -109.93871, in Montana, in hydrologic subbasin 10070002, at an elevation of about 4,056 feet, draining roughly 525 square miles.
- Can I use Boulder River at Big Timber, MT 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.