529 USGS stream gauges. Click one for its flow now, and how that compares with the median for today across the station’s whole record — the number that says whether a river is low, normal or high for the date rather than just large or small.
Cut at dams, and at the midpoint between consecutive gauges so each gauge sits inside its own reach. Never across a regulation boundary, so a reach is never part open and part closed.
Live water temperature on the trout reaches that have a gauge standing on them, straight from USGS. Trout bands, not steelhead ones — a trout river at 48°F is fishing well, where the same reading is only fair for a steelhead.
Every reach is drawn; the pale ones have no current reading. Most trout water has no gauge at all — there are far fewer up there than on the anadromous rivers — so expect more pale than coloured. A reading over a week old is treated as no reading.
Live water temperature on the reaches that have a gauge standing on them, straight from USGS. Filled by the bands the map paints from, so key and map cannot drift apart.
Every reach is drawn; the pale ones have no current reading — click one to see whether that is because there is no gauge, or because its gauge has stopped. A reading over a week old is treated as no reading at all. The 155 stations that do are shown too, so you can see which one is behind each colour — and which reaches are coloured from a gauge at their very top rather than the middle.
How each river fishes in the month on the date picker, for the species chosen above — from the research workbook.
Each river is rated as a whole, so every reach of it shares one colour. A month the river isn’t rated for is off season. Click a reach for its whole year. Closed water is shown too — this describes how the river fishes, not whether you may fish it.
The river’s standing quality for the species chosen above — from the research workbook.
This one ignores the date: the workbook rates a river once, not once per month. Closed water is shown too. For how a river fishes this month, use Seasonal conditions.
How good a trout fishery each water is, rated by hand — not from the research workbook, which covers steelhead and salmon only.
A water we haven’t rated scores 1, which means unrated — not poor. Most of California’s trout water has no rating yet, and hiding it would be worse than showing it grey. The rating ignores the date, and where a river is rated differently along its length — the upper and lower Kern, the upper and lower Owens — each part carries its own.
What is hatching in the month on the date picker — 2 points for every hatch at its peak, 1 for every one merely active, then graded into four steps against the river’s own best month.
Each river is shaded against its own best month, not against other rivers: a spring creek with six hatches is at its best when its six are out. So High means “good for here, now”, not “better than the next river”. Click a reach for the month’s score and what is coming off. Water with no hatch calendar is left undrawn.
One number per reach, from fishery quality, hatch activity, water temperature and river flow — averaged into a score from 1 (worst) to 4 (best).
Quality and hatch activity always count. Temperature and flow count only where a gauge reports and the river has bands written for it, so an unmeasured reach isn’t marked down for what nobody measured. Click a reach for the numbers behind its score.
Live discharge judged against each river’s own trout bands — 300 cfs is a trout river fishing well and a steelhead river running thin.
Three bands, not four: the trout list stops at High, so a river never reads as blown out. Every reach is drawn — pale means no reading, or no bands written for that river yet. Good scores 4, High 3 and Low 2 towards Current Conditions.
Live discharge judged against each river’s own bands — 500 cfs is a flood on Deer Creek and a drought on the Klamath.
The score peaks in the middle rather than at one end: a river can be too low or too high. Click a reach for its whole ladder. Every reach is drawn — pale means no current reading, or no bands written for that river. A negative reading is tidal, not low. Closed water is shown too.
One number per reach, from water temperature, river flow, seasonal conditions and fishery quality — averaged into a score from 0 (worst) to 4 (best).
Fishery quality and seasonal conditions always count: a river that isn’t rated, or a month that is off season, scores 0 — a good flow is no use where the fish aren’t. Temperature and flow count only where a gauge reports, so an unmeasured reach isn’t marked down for it. Click a reach to see the four numbers behind its score. Only reaches open on the selected date are scored — this is the layer that answers “should I go today”, while the others describe the water whatever its season.
Readings come straight from USGS when you click; nothing is stored. Reports and hatch timing come next.
When fish are in the river, and how it fishes — month by month. Pick a species, then a run.