San Juan River
The best month to fish the San Juan River is January. The month to avoid is June. Right now, in September, it is worth going.
- January: 71 out of 100
- February: 71 out of 100
- March: 71 out of 100
- April: 71 out of 100
- May: 36 out of 100
- June: 26 out of 100
- July: 71 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.
- Flow is well higher than normal — 1,440 CFS against a typical 786 CFS.
LIVE FROM USGS GAUGE 09368000 · EVERYTHING ELSE ON THIS PAGE IS A TWENTY-YEAR NORMAL
GAUGE 09368000 · COLOURED BY SEPTEMBER
Month by month
| MONTH | TYPICAL FLOW | RANGE (P20–P80) | WATER | AIR HIGH | RAIN | SCORE |
|---|---|---|---|---|---|---|
| January | 705 cfs | 533–805 | — | — | — | 71 |
| February | 682 cfs | 558–926 | — | — | — | 71 |
| March | 915 cfs | 580–1,043 | — | — | — | 71 |
| April | 934 cfs | 616–1,666 | — | — | — | 71 |
| May | 2,249 cfs | 1,375–4,780 | — | — | — | 36 |
| June | 3,060 cfs | 1,077–6,352 | — | — | — | 26 |
| July | 978 cfs | 747–1,463 | — | — | — | 71 |
| August | 746 cfs | 542–1,196 | — | — | — | 71 |
| SeptemberNOW | 786 cfs | 633–904 | — | — | — | 71 |
| October | 733 cfs | 604–881 | — | — | — | 71 |
| November | 763 cfs | 590–845 | — | — | — | 71 |
| December | 717 cfs | 558–808 | — | — | — | 71 |
WHERE THESE NUMBERS COME FROM
Flow and water temperature are medians of the monthly means reported by USGS gauge 09368000 over 2004-2023. 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 733–934 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 San Juan River is at its best in January, flows near 705 cfs.
← RIVERS GOING WELL IN SEPTEMBERRegulations, 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.