United States 
In numbers.
14m
Height
OpenStreetMap
354m³/s
Average flow
estimate
Apr–Jun
Nov
Best months
49MW
Water power
estimate
The water at Great Falls, month by month
It roars from March to July and from October to November.
The fullest months: from March to July and from October to November.
- 181 m³/sJan
- 206 m³/sFeb
- 544 m³/sMar
- 812 m³/sApr
- 959 m³/sMay
- 735 m³/sJun
- 457 m³/sJul
- 153 m³/sAug
- 238 m³/sSep
- 433 m³/sOct
- 501 m³/sNov
- 392 m³/sDec
From about 153 m³/s in the lowest month to 959 m³/s in the highest. Best months to go, with plenty of water and pleasant days: from April to June and November.
Estimate: the timing comes from rain, snowmelt and evaporation (NASA POWER, 1991–2020); the amounts from the river model of HydroATLAS (WaterGAP, 1971–2000). Dams upstream can change the real flow.
Waterfalls on the Potomac River in Maryland and Virginia
Great Falls is a waterfall in United States. The water falls 14 m.
Getting there.
- Great Fallsnearest town · 3.1 km in a straight line
- Parking 210 m awaynearest car park in OpenStreetMap, straight line
- Washington Dulles International Airport (IAD)nearest airport with scheduled flights · 19 km in a straight lineCar hire at IAD airport (Dulles)Discover Cars · Affiliate link↗
- From April to June and Novemberbest months to go (estimate)
Plan your visit
Stay, explore and get there
Some links above are affiliate links: if you book through them we may earn a commission, at no extra cost to you. It never changes what the data on this page says.
How big is it?
How big it really is.
Height of the drop as mapped in OpenStreetMap (© OpenStreetMap contributors). Buildings and the person are drawn at the same scale.
49 MW
About 354 m³/s falling 14 m: the power of the water as it drops.
- as much as 16 large wind turbines
- enough to power about 12,100 homes, if it were all turned into electricity
Power of falling water = density × gravity × flow × height. Average flow and height as shown above; an estimate.
Seen from the sky.
8 × 8 km of cloud-free satellite image, with what OpenStreetMap knows around the falls.
N
2 km
Sentinel-2 cloudless 2016 (EOX, CC BY 4.0), 8 × 8 km, north up. Points © OpenStreetMap contributors.
The line follows the river as mapped in OpenStreetMap; heights from the 30 m Copernicus model, which smooths narrow drops — the published height of the falls is the one above.
Around the falls the river drops 26 m in 2.7 km. Here the river runs about 44 m below the lower rim of its valley.
What is around.
- 11viewpointsGreat Falls Overlook, Overlook 1, Overlook 2 and 8 more
- 10waymarked walking routesPotomac Heritage National Scenic Trail (right bank), ADT - Maryland - Seg 4, Riverbend Road Trail and 7 more
- 9car parks
- —swimming spots
- 30picnic sites
- 4toilets
- 11information boards and visitor centres
- —bus stops within 1 km
- —other named waterfalls within 4 km
- —caves
- 8campsitesCamp Fraser, Marsden Tract Group Campsite, Lake Fairfax Family Campground and 5 more
- 2hotels, B&Bs and huts within 6 kmWilliam F. Bolger Center
- 2restaurants and cafés within 3 km
Counted in OpenStreetMap, the map anyone can edit, up to 2 km around the falls (unless noted). A low number may just mean nobody has mapped it yet. © OpenStreetMap contributors (ODbL).
Towns nearby
- Great Falls3.1 km in a straight line
- Potomac4.4 km in a straight line
- Wolf Trap7.0 km in a straight line
- Travilah8.0 km in a straight line
- Dranesville8.1 km in a straight line
- Reston8.3 km in a straight line
- Cabin John8.5 km in a straight line
- Tysons9.0 km in a straight line
Weather
The weather, month by month.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Afternoon °C | 4 | 6 | 12 | 19 | 24 | 29 | 32 | 31 | 27 | 20 | 13 | 7 |
| Night °C | -4 | -4 | 0 | 6 | 12 | 18 | 20 | 20 | 15 | 8 | 2 | -2 |
| Rain & snow (mm) | 65 | 67 | 81 | 94 | 120 | 116 | 108 | 95 | 108 | 99 | 77 | 87 |
| Wet days | 9 | 8 | 10 | 10 | 14 | 14 | 15 | 13 | 11 | 8 | 8 | 9 |
| Sun h/day | 3.9 | 4.9 | 5.4 | 6.5 | 6.8 | 8.1 | 8.2 | 7.4 | 6.4 | 5.3 | 4.6 | 3.6 |
| Snow on the ground (cm) | 13 | 13 | 6 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 10 |
Long-term averages 1991–2020 (NASA POWER) for a cell about 55 km wide, with temperatures carried to the height of the falls (37 m) at −6.5 °C per 1,000 m. Not a forecast.
Photos
Through visitors' eyes.
Recent years
Wet years and dry years
Rain of each month as a share of the 1991–2020 average. A wet season above 100 % usually means a fuller waterfall.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020 | 119% | 100% | 73% | 140% | 45% | 77% | 82% | 191% | 72% | 139% | 154% | 131% |
| 2021 | 69% | 144% | 78% | 59% | 60% | 81% | 58% | 138% | 125% | 79% | 28% | 18% |
| 2022 | 100% | 68% | 67% | 65% | 112% | 60% | 90% | 82% | 73% | 64% | 94% | 110% |
| 2023 | 54% | 77% | 54% | 85% | 27% | 60% | 86% | 59% | 117% | 32% | 79% | 160% |
| 2024 | 233% | 81% | 136% | 72% | 79% | 38% | 63% | 166% | 86% | 9% | 51% | 83% |
| 2025 | 63% | 96% | 57% | 64% | 171% | 109% | 123% | 26% | 55% | 56% | 36% | 42% |
130% wetter than usual 70% drier than usual
Compare with the waterfalls nearby.
Great Falls
United States
- 14 mHeight
- 354 m³/sAverage flow
- Apr–Jun, NovBest months
About these numbers
| Names, height, width, river | Wikidata (Q1475394) · CC0 |
|---|---|
| Height of the drop | © OpenStreetMap contributors · ODbL |
| River flow and catchment | HydroATLAS / RiverATLAS v1.0 (Linke et al. 2019) · CC BY 4.0 |
| Climate | NASA POWER, 1991–2020 |
| Relief, river profile, 3D model | Copernicus DEM GLO-30 · © DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA |
| Paths, viewpoints, parking | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
Every figure is an average, an estimate or a count from a public dataset. Licences and methods: data sources.
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