Swimming in Glaslyn — the copper-green lake at 600 metres beneath Yr Wyddfa's summit — is cold, brief, and entirely memorable. The lake's colour, its altitude, the surrounding ridges, and the knowledge that you are swimming in a high mountain lake in the shadow of the highest point in Wales and England: this is wild swimming at a level of setting that few British locations can match. This is Experience #88 of the Snowdonia 100.
Practical Notes
| Temperature | 6–14°C depending on season — cold year-round |
| Best time | July–September for the warmest conditions |
| Access | Via Miners' Track from Pen-y-Pass — 45 minutes to the lake |
| Entry point | The outflow area on the eastern shore |
| Safety | Cold water shock is real — acclimatise carefully, never swim alone |
The Experience
The water is clear and cold, the copper-green colour coming from dissolved copper minerals rather than any biological cause. The entry should be gradual — cold water shock is a genuine physiological hazard, not a figure of speech, and entering quickly can cause involuntary gasping and loss of swimming ability. Once acclimatised, even a brief swim — five to ten minutes — is sufficient to experience the full quality of the place. Exit promptly, warm up, and eat something.
The Setting
The ridges of Yr Wyddfa, Crib Goch, and Y Lliwedd rise on three sides of the lake. No roads, no buildings, no sounds beyond the wind and the occasional call of a raven. The copper-green water and the grey-brown rock and the sky: this is mountain landscape at its most elemental, and to be in the water rather than on the shore changes the relationship to the place in ways that are difficult to describe and easy to experience.
Experience #88 of 100 — Challenges and Adventures category.
Independently written — Snowdon.com