Yellowstone River
The best month to fish the Yellowstone River is January. The month to avoid is June. Right now, in August, it is worth going.
- January: 71 out of 100
- February: 65 out of 100
- March: 71 out of 100
- April: 71 out of 100
- May: 57 out of 100
- June: 34 out of 100
- July: 36 out of 100
- August: 71 out of 100
- September: 71 out of 100
- October: 71 out of 100
- November: 71 out of 100
- December: 71 out of 100
This gauge does not report water temperature, so the check that would rule out water too warm to fight a fish in cannot run for this month. Treat the score as flow and season only, and ask a local shop about temperature before you travel in warm weather.
GAUGE 06329500 · COLOURED BY AUGUST
Month by month
| MONTH | TYPICAL FLOW | RANGE (P20–P80) | WATER | AIR HIGH | RAIN | SCORE |
|---|---|---|---|---|---|---|
| January | 5,899 cfs | 5,098–6,748 | — | — | — | 71 |
| February | 6,467 cfs | 5,232–7,974 | 32.0°F | — | — | 65 |
| March | 7,030 cfs | 5,825–13,280 | — | — | — | 71 |
| April | 9,564 cfs | 6,591–12,030 | — | — | — | 71 |
| May | 18,025 cfs | 15,390–25,180 | 58.9°F | — | — | 57 |
| June | 41,035 cfs | 23,960–44,860 | — | — | — | 34 |
| July | 18,525 cfs | 9,757–27,520 | — | — | — | 36 |
| AugustNOW | 4,829 cfs | 3,479–8,837 | — | — | — | 71 |
| September | 4,971 cfs | 3,778–7,846 | — | — | — | 71 |
| October | 7,802 cfs | 6,135–10,230 | — | — | — | 71 |
| November | 6,963 cfs | 6,349–8,794 | — | — | — | 71 |
| December | 5,860 cfs | 5,418–7,520 | — | — | — | 71 |
WHERE THESE NUMBERS COME FROM
Flow and water temperature are medians of the monthly means reported by USGS gauge 06329500 over 2005-2024. Air temperature and precipitation are ten-year normals from Open-Meteo at this river’s gauge coordinates.
The window is deliberate. USGS’s own full-record statistics for a dammed river reach back before the dam — at Lees Ferry, to 1922, forty-one years before Glen Canyon closed — and describe a river that no longer exists.
Flow is scored against this river’s own fishable band of 5,899–9,564 cfs. There is no universal band: 8,000 cfs is low water on a big tailwater and a flood on a spring creek.
Water temperature is a ceiling rather than a weight. Above about 68°F a trout that is fought and released frequently dies anyway, so no month above that line is scored as worth booking, however good its flow.
The Yellowstone River is at its best in January, flows near 5,899 cfs.
← RIVERS GOING WELL IN AUGUSTRegulations, licences and access change without notice and are not reproduced here as fact — check the state agency before you travel. A median describes twenty years; it does not forecast your week. Source: U.S. Geological Survey, National Water Information System.