Claerwen Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Claerwen Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Claerwen Reservoir today is 10.9°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
❌ As of today, the minimum water temperature ranges from 50°F (10°C) to 54°F (12°C). The water is slightly warmer, but still cool for most people. Swimming in such conditions is possible, but for most people, the time spent in the water should be limited to avoid hypothermia. Even experienced swimmers may feel discomfort if they stay in the water for too long. To improve comfort and safety, a wetsuit 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 | 11.2°C | 18.0°C | |
| JUN 4 | 11.2°C | 18.0°C | |
| JUN 5 | 11.2°C | 18.0°C | |
| JUN 6 | 11.2°C | 18.0°C | |
| JUN 7 | 10.9°C | 18.0°C | |
| JUN 8 | 10.9°C | 18.0°C | |
| JUN 10 | 10.9°C | 18.0°C | |
| JUN 11 | 18.0°C | 11.3°C | |
| JUN 12 | 18.0°C | 11.6°C | |
| JUN 13 | 18.0°C | 12.0°C | |
| JUN 14 | 18.0°C | 12.3°C | |
| JUN 15 | 18.0°C | 12.7°C | |
| JUN 16 | 18.0°C | 13.0°C | |
| JUN 17 | 18.0°C | 13.4°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 | 0°C | 3°C | 6°C |
| February | 0°C | 4°C | 7°C |
| March | 2°C | 6°C | 9°C |
| April | 6°C | 10°C | 13°C |
| May | 8°C | 15°C | 22°C |
| June | 10°C | 18°C | 25°C |
| July | 16°C | 21°C | 26°C |
| August | 16°C | 21°C | 26°C |
| September | 11°C | 17°C | 22°C |
| October | 8°C | 12°C | 15°C |
| November | 3°C | 7°C | 10°C |
| December | 0°C | 4°C | 7°C |
Claerwen Reservoir: Water Temperature by Location
Claerwen Reservoir: Weather Forecast
June 9
June 10
June 11
June 12
June 13
Location & Local Information
Claerwen Reservoir, the newest and largest of the dams in the Elan Valley Estate in Mid Wales, is a crucial part of the water supply network and consequently, swimming is strictly prohibited. This restriction is enforced for both public safety and to maintain the water's pristine quality. The reservoir is characterised by its cold, deep water, where temperatures even in high summer generally remain well below 16∘C (61∘F), dropping to a chilling 4∘C to 8∘C (39∘F to 46∘F) in winter. The sudden onset of cold water shock and submerged hazards make unauthorised entry extremely dangerous.
Despite the ban on swimming, the Claerwen Valley, with its rugged, mountainous backdrop, is highly valued for other outdoor pursuits. It is a fantastic destination for walkers, cyclists, and mountain bikers, with a variety of trails, including challenging routes around the dam itself. Claerwen is part of the wider Elan Valley, where visitors can explore the other impressive Victorian dams, enjoy birdwatching, or visit the nearby town of Rhayader, known for its Red Kite Feeding Centre.