Winnebago River At Mason City flow report
As of July 12, 2026, Winnebago River At Mason City is flowing at 392 cfs with a gage height of 5.93 ft, receding 20% over the past 24 hours. Source: USGS gauge #05459500, refreshed throughout the day.
Historical Data
Winnebago River At Mason City at a glance
How Winnebago River At Mason City is running right now, where it sits on the map, and the key gauge stats.
Winnebago River At Mason City is flowing at 392 cfs, with the water sitting 5.93 ft at the gage. Flow is down 20% since yesterday as the gauge recedes.
This is USGS gauge #05459500 in Iowa. Over the past 10 days the average has been 533 cfs, peaking at 813 cfs.
Over the next 5 days, Winnebago River At Mason City is expected to recede from today's 392 cfs, toward roughly 335 cfs by 2026-07-17 (likely range 123-910 cfs) -- drier than normal for the date.
For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the Iowa flow report.
Streamflow Forecast
Powered by PULSE — Snoflo’s Predictive Unified Learning & Simulation Engine, which learns from how this river has answered every past storm, snowmelt, and dry spell to forecast where it’s headed with a precision generic models can’t match.
How does this compare to past years?
Year-over-year overlay, annual peak discharge, the full distribution of daily flows on record, and the gauge's rating curve.
Weather Forecast
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day forecast
Daily temperatures, snow, and rain projected over the next two weeks.
Winnebago River At Mason City
The river is a tributary of the Shell Rock River and has several dams, including the Winnebago Dam. The river's flow is primarily from snowmelt and precipitation, with spring and summer being the peak seasons. The watershed is mainly agricultural land, with some urban areas. The river has experienced flooding in the past, with a significant flood in 2008 causing millions of dollars in damages. The water quality is impacted by agricultural runoff and urban development. The Winnebago River is popular for fishing and recreational activities, with smallmouth bass and walleye being the most common catches.
Nearby streamflow levels
Cross-check Winnebago River At Mason City's discharge against nearby gauges to spot whether the change here is local or regional.
| Gauge | Streamflow |
|---|---|
| Winnebago River At Mason City | 392 cfs |
| Cedar River At Charles City | 5,430 cfs |
| Cedar River Near Austin | 940 cfs |
| Iowa River Near Rowan | 875 cfs |
| Little Cedar River Near Ionia | 4,470 cfs |
| Shell Rock River At Shell Rock | 5,370 cfs |
Nearby snowpack data
Snowpack at SNOTEL stations near Winnebago River At Mason City. Spring snowmelt is the dominant driver of streamflow in mountain basins -- a deep snowpack upstream means more runoff later in the season.
| SNOTEL station | Snowpack |
|---|---|
| Charles City | 0 in |
| Hampton | 0 in |
| Allison | 0 in |
| Elma Iowa | 0 in |
| Bricelyn | 0 in |
| Iowa Falls | 0 in |
Plan a trip
Reservoirs, boat launches, river runs, and fishing spots within driving distance of Winnebago River At Mason City.
Nearby reservoirs
See all →
River levels & flood safety
- Read the level before you go
- A river that's runnable at one flow can be deadly at another. Check current discharge and gage height — like the values shown above — against the flood-stage thresholds, and remember levels can spike fast after rain or a dam release.
- Respect cold water
- Snowmelt rivers run cold even in summer. Sudden immersion triggers cold-water shock and saps strength within minutes. Wear a PFD, dress for the water temperature (not the air), and never wade or paddle alone.
- Watch for swiftwater hazards
- Strainers (downed trees), undercut rocks, and low-head dams are the deadliest features on moving water. High, fast, muddy water hides them. If in doubt, scout from shore and portage.
- Mind flash floods & releases
- Narrow canyons can flood from a storm miles upstream, and dam-controlled reaches can rise without warning. Know the forecast, the release schedule, and your exit before you launch.
Track Winnebago River At Mason City in the Snoflo app
Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when Winnebago River At Mason City crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.
About Winnebago River At Mason City
Where does the streamflow data for Winnebago River At Mason City come from?
Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 05459500. Snoflo refreshes the time series throughout the day. Forecasts come from the NOAA / yr.no feed Snoflo's iOS app uses.
How often is the report updated?
USGS gauges report continuously (typically every 15 minutes). Snoflo pulls fresh values throughout the day — look for the "as of" timestamp on the streamflow hero card.
What's the difference between discharge and gage height?
Discharge (cubic feet per second, or cfs) is the volume of water flowing past the gauge each second. Gage height is how high the water sits at the gauge (feet). They're related by a rating curve specific to each gauge — higher water means more flow, but the exact ratio depends on channel shape.
How is "percent of median" calculated?
Today's discharge is compared to the historical median discharge on this calendar day across the gauge's full record. 100% = right on median; 200% = a very high year; 30% = a drought-level low.
What are flood stages, and is this river safe right now?
Flood stages are NWS-defined gage-height thresholds — Action, Minor, Moderate, Major — marking when nearby roads or floodplains start to be affected. "Safe" depends on your activity and skill: a level that's a fun paddle for an expert can be lethal for a wader. Always check the current level against the thresholds above and the safety links, and when in doubt, stay off the water.
Can I get alerts when Winnebago River At Mason City rises?
Yes — flow alerts are managed in the Snoflo iOS app. Favorite this gauge, set a streamflow threshold (e.g. "alert me when discharge crosses 5,000 cfs"), and you'll get a push the moment USGS reports the crossing.
Access the free Winnebago River At Mason City report
Create your free account to track this river — and everything else you love on the water.
- Flow alerts — get pinged the moment this river hits your range
- Save favorites — every river, lake & snowpack in one place
- Full history & forecasts — plus the free iPhone app