River Tywi · Afon Tywi
All five gauges on the River Tywi are normal.
Read from 5 river-level gauges at 12:00 on 28 October 2026 GMT, and read again every fifteen minutes.
See the River Tywi on the live map →Every gauge on the River Tywi, right now
| Gauge | km above the mouth |
Level now |
Against its record |
Percentile | Trend |
|---|---|---|---|---|---|
| Ystradffin No2near Rhandir-mwynregulated | 101 | 0.09 m | Normal | 7th | ▬steady |
| Dolau Hirionnear Llandovery (Llanymddyfri) | 84 | 0.60 m | Normal | 72nd | ▼falling |
| Manorafonnear Llandeilo | 63 | 1.73 m | Normal | 83rd | ▬steady |
| Ty Castellnear Nantgaredig | 32 | 2.21 m | Normal | 86th | ▬steady |
| Capel Dewinear Nantgaredig | 31 | 2.03 m | Normal | 89th | ▬steady |
The percentile is where a gauge's latest reading sits in its own record of readings, not how full the channel is. A river sits low most of the time, so a high percentile takes surprisingly little water: at Beddgelert on the Glaslyn, with thirty-six years of record, the ninety-fourth percentile is about 1.05 m - 1.38 m below the highest level ever recorded there.
The course of the River Tywi
About this river
From its highest reach down to its mouth near St Ishmael, the Afon Tywi runs 117 km. The lowest 27 km are tidal, where a gauge reads the tide as much as the river. The course above is drawn in two weights: the bright line is where Ordnance Survey Open Rivers calls the channel the Afon Tywi, and the faint line, about 10 km of it, is the same water running under another name, past a lake or a weir pool. Its gauges hold between 25 and 42 years of readings, and that is what today's levels are compared with.
- Llyn Brianne RES - a reservoir. Its gauge measures how far the water has drawn down from a fixed mark, which is not a river level, so it is not in the table above
- Ystradffin No1 - a rain gauge near Rhandir-mwyn, not a river level
- Pothouse Wharf - on the tidal Tywi at Carmarthen (Caerfyrddin), reading 2.95 m. What a gauge reads here is the tide as much as the river, so it is not ranked against a record