Lake Llyn Gwynant — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Llyn Gwynant, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Llyn Gwynant today is 18.8°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| JUN 25 | 16.9°C | 20.9°C | |
| JUN 26 | 16.9°C | 20.9°C | |
| JUN 27 | 19.1°C | 20.9°C | |
| JUN 28 | 19.1°C | 20.9°C | |
| JUN 29 | 18.5°C | 20.9°C | |
| JUN 30 | 18.9°C | 20.9°C | |
| JUL 1 | 18.8°C | 23.0°C | |
| JUL 2 | 18.8°C | 23.0°C | |
| JUL 3 | 23.0°C | 19.0°C | |
| JUL 4 | 23.0°C | 19.2°C | |
| JUL 5 | 23.0°C | 19.4°C | |
| JUL 6 | 23.0°C | 19.6°C | |
| JUL 7 | 23.0°C | 19.9°C | |
| JUL 8 | 23.0°C | 20.1°C | |
| JUL 9 | 23.0°C | 20.3°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 2°C | 6°C | 9°C |
| February | 2°C | 6°C | 9°C |
| March | 3°C | 7°C | 10°C |
| April | 7°C | 11°C | 14°C |
| May | 10°C | 17°C | 22°C |
| June | 14°C | 21°C | 27°C |
| July | 18°C | 23°C | 28°C |
| August | 17°C | 22°C | 27°C |
| September | 13°C | 19°C | 24°C |
| October | 10°C | 14°C | 18°C |
| November | 5°C | 9°C | 12°C |
| December | 2°C | 6°C | 9°C |
Lake Llyn Gwynant: Water Temperature by Location
Lake Llyn Gwynant: Weather Forecast
July 3
July 4
July 5
July 6
Location & Local Information
Llyn Gwynant is a natural lake in Snowdonia National Park, nestled in a picturesque valley beneath the slopes of Snowdon. Fed by clear mountain streams, the lake’s water remains cool for most of the year. In winter, temperatures often fall to around 3–5 °C (37–41 °F), while in spring they rise slowly to about 8–10 °C (46–50 °F). During summer, the surface water can reach 15–17 °C (59–63 °F) on calm, sunny days, though shaded or deeper parts stay several degrees cooler. By autumn, the lake cools again toward 9–11 °C (48–52 °F), reflecting the fresh, temperate conditions typical of upland North Wales.
Swimming in Llyn Gwynant is allowed and quite popular, especially during the warmer months. The water is clean and clear, and the gently shelving shoreline makes it suitable for both casual swimmers and more experienced open-water enthusiasts. Wetsuits are common outside midsummer, as the lake retains a mountain chill. Visitors often combine swimming with kayaking, paddleboarding, or picnicking along the scenic banks. The surrounding area offers stunning walks and viewpoints, including routes toward Snowdon, Llyn Dinas, and the Nant Gwynant Pass. The nearby village of Beddgelert and the waterfalls at Aberglaslyn Gorge make the lake a favourite spot for outdoor recreation in Snowdonia.