About this river
Flathead River is a 9.0 mile river near Adventure Missoula in Montana. Streamflow is measured at the USGS gauge Flathead River at Perma MT (site 12388700). The National Hydrography Dataset places it at stream order 7. Reach geometry comes from the USGS National Hydrography Dataset.
Typical flow by month
1984 to 2025
Flathead River typically runs highest in June, at a median 23,250 cfs, and lowest in September, at 6,305 cfs. The highest flow on record for any single day is 55,200 cfs, in 2022.
| Month | Typical (cfs) | Usual range (cfs) | Relative level |
|---|---|---|---|
| January | 9,800 | 8,530 to 11,700 | |
| February | 8,870 | 7,670 to 11,200 | |
| March | 8,370 | 6,790 to 9,950 | |
| April | 9,440 | 6,480 to 14,400 | |
| May | 15,900 | 12,400 to 23,600 | |
| June | 23,250 | 14,800 to 33,400 | |
| July | 12,700 | 9,080 to 15,400 | |
| August | 6,510 | 5,120 to 8,680 | |
| September | 6,305 | 4,750 to 8,585 | |
| October | 7,470 | 5,580 to 9,530 | |
| November | 9,300 | 7,050 to 11,300 | |
| December | 10,100 | 8,890 to 12,200 |
Typical is the median of each month’s daily median values, and the usual range runs from the median 25th to the median 75th percentile, across about 42 years of record. Statistics published by the US Geological Survey for Flathead River at Perma MT (site 12388700). Conditions on any given day can fall well outside the usual range. Check the current reading before you go.
Embed this gauge on your site
Paste this snippet anywhere, an outfitter page, a club site, a trip report, to show Flathead River's live streamflow, water level and 7-day trend. It reads the USGS gauge directly, updates itself, and links back here.
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