Three major falls on the Genesee River in the Grand Canyon of the East, with the flow-setting dam conveniently DOWNSTREAM, so what comes over is the river's own weather.
Mid March through June
Big water window
in a typical year
Snowmelt
What drives it
Genesee River
Live USGS
Data on this page
gauge 04223000
NY State Parks
Managed by
their rules govern
Trail status, closures and safety rules belong to each falls' managing agency, named and linked on every page.
The season
What fills Letchworth Falls, and when
The Genesee at Letchworth is refreshingly unmanaged: the Mount Morris flood control dam sits below the park, so the three falls carry the river's natural snowmelt-and-rain calendar, big from mid March through June and steady but visibly leaner by fall. The Portageville gauge at the park's south entrance reads the river immediately upstream of the Upper Falls.
Typical best flow: Mid March through June
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What the agency itself says
The Genesee River roars through the gorge over three major waterfalls between cliffs--as high as 600 feet in some places—surrounded by lush forests.
Letchworth State Park (New York State Parks)What a snowmelt year looks like at full send: Palouse Falls in mid April, when the Palouse River is still carrying the melt. The same falls in late August is a ribbon. Timing is most of the visit. “04-15-14-palouse” — Dsdugan — CC0
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Right now
What Genesee River is doing today
Flow at the gauge now
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USGS median for Oct 15
Not published
Gauge: USGS 04223000 Genesee River at Portageville NY, immediately upstream of the Upper Falls, at the park's south entrance. The gauge reads the river, not the brink of the falls, so treat it as the trend line rather than a turnstile.
Source: USGS Water Services (National Water Information System). Instantaneous values and daily statistics services. U.S. Geological Survey data are works of the United States Government and are in the public domain. Gauge verified 2026-08-27.
The other half of the story: the same Palouse Falls in late August. Nothing is wrong; this is what a snowmelt river does every year once the melt is spent. “Palouse Falls 20100829” by Mark Wagner, CC BY-SA 2.5
Getting there
Access, in the agency's words and ours
Overlooks and trails line the gorge from the park roads; New York State Parks notes Trail 7 from Middle Falls to the Genesee Arch Bridge is permanently closed, and winter turns the park toward snow tubing and skiing.
A big eastern river doing waterfall work (Great Falls of the Potomac, NPS photo). Letchworth's Genesee runs the same natural calendar through its 600 foot gorge. “Great Falls of the Potomac River in November, 2012” — National Park Service — Public domain
Common questions
Letchworth Falls flow season FAQ
The reliable big-water window is Mid March through June. The Genesee at Letchworth is refreshingly unmanaged: the Mount Morris flood control dam sits below the park, so the three falls carry the river's natural snowmelt-and-rain calendar, big from mid March through June and steady but visibly leaner by fall. The Portageville gauge at the park's south entrance reads the river immediately upstream of the Upper Falls.
This page reads the USGS gauge on Genesee River (Genesee River at Portageville NY, immediately upstream of the Upper Falls, at the park's south entrance) live in your browser, and shows the latest flow next to the median USGS publishes for today's date, so you can see where today sits in the year. The gauge reads the river, not the brink, so treat it as the trend rather than a turnstile.
No; the Genesee is a substantial river all year. The seasonal swing shows in sound and spray rather than in bare rock, and the live gauge on this page reads it a mile from the falls.
Letchworth State Park (New York State Parks). Overlooks and trails line the gorge from the park roads; New York State Parks notes Trail 7 from Middle Falls to the Genesee Arch Bridge is permanently closed, and winter turns the park toward snow tubing and skiing. Trail status, closures and safety rules are theirs, and their page is linked on this one; nothing here overrides what they publish.
Yosemite Falls in May, running on snowmelt that will be gone by late summer. The National Park Service tells visitors the falls can be dry by August, which is why every falls page here starts from its watershed. “Tourists below Yosemite Falls (39832011431)” by Mike McBey, CC BY 2.0
The most famous falls on the continent runs on a 1950 treaty: 100,000 cfs must come over during tourist season daytime hours, half that the rest of the time, with the balance sent to power plants.
A 215 foot single plunge past 400 foot gorge cliffs near Ithaca, taller than Niagara, biggest with the Finger Lakes spring runoff and thin by late summer.
New York's tallest waterfall by the DEC's own account, a 260 foot two-tier drop in the Catskills painted by the Hudson River School and treated with respect by everyone who reads the DEC's warnings.
Flow windows are typical-year climatology drawn from the driver and the agency language quoted above, not forecasts. Live readings and per-date percentiles are U.S. Geological Survey data, public domain; the above-or-below-typical line is our comparison and is labelled as such. Access, trail and safety information belongs to Letchworth State Park (New York State Parks). National picture: waterfall season across the US → Hero image: “Great Falls of the Potomac River in November, 2012” — National Park Service — Public domain
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