USGS Streamgage 09471550
San Pedro River near Tombstone, AZ
San Pedro River near Tombstone, AZ is USGS streamgage 09471550 in Arizona, monitoring river discharge in hydrologic subbasin 15050202. It drains a watershed of about 1,740 square miles. Discharge records at this site go back to 1967. Typical flow runs near 15.3 cfs in July and 7.3 cfs in April, with the higher of the two arriving in July.
Gauge details
- State
- Arizona
- Drainage area
- 1,740 sq mi
- Gauge elevation
- 3,787 ft
- Subbasin (HUC-8)
- 15050202
- Coordinates
- 31.75144, -110.20133
- USGS site number
- 09471550
- Records begin
- 1967-04-18 (59 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 59 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 | 2.1 | 11.9 | 37 | |
| February | 5.3 | 12.3 | 40.5 | |
| March | 6.1 | 11.2 | 48.8 | |
| April | 3 | 7.3 | 20 | |
| May | 0 | 1.8 | 9.2 | |
| June | 0 | 0 | 3.7 | |
| July | 0 | 15.3 | 236.8 | |
| August | 0.1 | 32 | 393 | |
| September | 0 | 7.7 | 105.9 | |
| October | 0 | 1.2 | 38.5 | |
| November | 0 | 3.9 | 21.3 | |
| December | 0.1 | 9.4 | 31.6 |
All values in cubic feet per second (cfs).
Common questions
- When does San Pedro River near Tombstone, AZ normally run highest?
- August, on the long-term record. The median daily flow that month is about 32 cfs, against 0 cfs in June, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for San Pedro River near Tombstone, AZ?
- It depends on the month. In January, half of days historically fall near 11.9 cfs, with the middle 80% of days between 2.1 and 37 cfs. The month-by-month table on this page gives the full range.
- How long has San Pedro River near Tombstone, AZ been measured?
- Discharge records at USGS site 09471550 begin in 1967, about 59 years, covering roughly 9,126 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is San Pedro River near Tombstone, AZ?
- The gauge sits at 31.75144, -110.20133, in Arizona, in hydrologic subbasin 15050202, at an elevation of about 3,787 feet, draining roughly 1,740 square miles.
- Can I use San Pedro River near Tombstone, AZ 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.