Lake Llyn y Fan Fach — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Llyn y Fan Fach, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Llyn y Fan Fach today is 9.9°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
❌ As of today, the minimum water temperature ranges from 47°F (8°C) to 50°F (10°C). This is still cool water, suitable only for experienced swimmers or those accustomed to cold water. Swimming in such conditions is possible, but not recommended for prolonged periods. Extra caution should be taken during extended exposure, as the cold water can cause heat loss and lead to hypothermia. For added comfort, special clothing can be used. 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 3 | 9.9°C | 17.9°C | |
| JUN 4 | 9.9°C | 17.9°C | |
| JUN 5 | 9.9°C | 17.9°C | |
| JUN 6 | 9.9°C | 17.9°C | |
| JUN 7 | 9.9°C | 17.9°C | |
| JUN 8 | 9.9°C | 17.9°C | |
| JUN 10 | 9.9°C | 17.9°C | |
| JUN 11 | 17.9°C | 10.3°C | |
| JUN 12 | 17.9°C | 10.7°C | |
| JUN 13 | 17.9°C | 11.1°C | |
| JUN 14 | 17.9°C | 11.5°C | |
| JUN 15 | 17.9°C | 11.9°C | |
| JUN 16 | 17.9°C | 12.3°C | |
| JUN 17 | 17.9°C | 12.7°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 | 1°C | 5°C | 8°C |
| February | 2°C | 6°C | 9°C |
| March | 4°C | 8°C | 11°C |
| April | 6°C | 10°C | 14°C |
| May | 8°C | 14°C | 20°C |
| June | 9°C | 18°C | 26°C |
| July | 17°C | 22°C | 27°C |
| August | 16°C | 21°C | 26°C |
| September | 13°C | 19°C | 24°C |
| October | 9°C | 13°C | 17°C |
| November | 4°C | 8°C | 11°C |
| December | 2°C | 6°C | 9°C |
Lake Llyn y Fan Fach: Water Temperature by Location
Lake Llyn y Fan Fach: Weather Forecast
June 9
June 10
June 11
June 12
June 13
Location & Local Information
Llyn y Fan Fach is a remote glacial lake in the western Brecon Beacons, surrounded by steep cliffs and grassy ridges that create one of the most dramatic landscapes in South Wales. Situated at an elevation of about 500 metres, the lake remains cold throughout the year. In winter, the water temperature often drops to around 2–4 °C (36–39 °F), with occasional surface ice during cold spells. In spring, it slowly rises to 7–9 °C (45–48 °F), while in summer it can reach 12–14 °C (54–57 °F) on calm, sunny days. By autumn, the temperature usually falls again to around 8–10 °C (46–50 °F). The mountain climate and constant inflow from cool streams keep the water consistently fresh and clear.
Swimming in Llyn y Fan Fach is permitted, though the cold temperature and remote setting make it suitable mainly for experienced wild swimmers. The lake’s steep sides and changeable weather require caution, but its purity and stillness offer a unique experience for those prepared for chilly water. Many visitors take short dips after hiking up from the valley below. The area is also known for its legend of the Lady of the Lake and offers excellent walking routes to nearby Llyn y Fan Fawr and along the Carmarthen Fans ridges.