About Waderly
Waderly is a free web app that shows live river levels, streamflow and water temperature from more than 17,900 public USGS stream gauges across 52 US states and territories, then tells you what those numbers mean for fishing or paddling today.
Why it exists
Deciding whether to go used to mean four browser tabs: the USGS gauge for flow, a weather site for the forecast, a state agency page for stocking or regulations, and a map for access. Each one gives you a number. None of them answers the actual question, which is whether the water is worth the drive this morning.
Waderly puts those sources on one page and takes the extra step of interpreting them. Not “71°F” but “71°F, warming past the 68°F trout comfort zone — fish early morning, or target warmwater species like smallmouth bass.”
How it works
Enter a zip code, city or waterway name. Waderly finds the stream gauges near you and maps them with their current readings. Open a gauge and you get the live flow in cubic feet per second, gauge height in feet, and water temperature where the sensor exists — each stamped with the time it was measured.
Around that it layers the National Weather Service forecast and any active flood or severe-weather alerts, barometric pressure trend, solunar feeding windows computed from sun and moon position, tide predictions on tidal water, trout stocking schedules, state wild-trout designations, public land boundaries for legal access, and the regulations that apply to that stretch.
Flow is shown against the historical median for that calendar date, because a bare number means little on its own: 300 cfs is a flood on a small creek and a drought on a big river. What matters is high, low or normal for right now.
Where the numbers come from
All of it is public government data, read directly. Waderly does not resell anyone's feed and does not use crowd-sourced or user-reported readings.
- USGS Water Services — streamflow (parameter 00060), gauge height (00065) and water temperature (00010), plus the historical daily statistics used for the seasonal comparison
- National Weather Service — forecasts, current observations, and active alerts
- NOAA CO-OPS — tide predictions
- NOAA National Water Prediction Service — river forecasts with action and flood stages
- EPA — water-quality advisories
- State agency feeds — trout stocking, wild trout waters, public lands, access points and regulations
USGS gauges report every 15 to 60 minutes and Waderly reads them live. You can verify any reading yourself against waterdata.usgs.gov — we explain how on the USGS gauge lookup guide.
What Waderly cannot tell you
Worth being straight about the limits, because a confident wrong answer is worse than no answer.
- A gauge measures one point. Conditions above a tributary junction, below a dam release, or several miles upstream can differ sharply from the reading.
- Only about one gauge in three reports water temperature. Where a sensor does not exist, Waderly says so rather than estimating. Carry a stream thermometer.
- It does not know where the fish are. It tells you what the water is doing. Reading the water is still your job.
- On tidal water, instantaneous discharge is meaningless — it swings with the tide and can read negative. Waderly suppresses cfs on those stations and shows stage instead.
- Upstream agencies occasionally go down or return stale data. When that happens the timestamp on the page will show it. Trust the timestamp.
What it costs
Waderly is free. Every gauge page, every live reading and the full map work with no account and no paywall. An optional Waderly Pro subscription adds a larger saved-water watchlist and automatic flow alerts that tell you when a river you care about comes into shape. There are no ads and no investors — subscriptions are what keep it independent.
Who builds it
Waderly is built by Dreki Labs. Found a bug, or want your state's data covered? There are report and request links in the app footer, or email [email protected].
Waderly is not…
Waderly (waderly.app) is a fishing and river conditions app. It is unrelated to Wader, the aviation software at wader.app and waderaviation.com, and unrelated to Cara (cara.app), the art portfolio network. The name collision confuses search engines and assistants regularly, so: if you were told there is no app called Waderly, this is it.
Start here
- Check conditions near you — enter a zip code
- Coverage — every state and what data each one has
- Is a creek too warm to fish?
- What water temperature is too warm for trout?
- How to check the USGS gauge for a creek near you
- All guides