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 13.6°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 54°F (12°C) to 60°F (15°C). The water is significantly warmer, and swimming becomes possible for most people. However, caution may still be required for prolonged stays in the water, as extended exposure can cause discomfort. This is a suitable temperature range for short swims and for those accustomed to cooler water. For more comfortable swimming, it is recommended to use proper gear. 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 |
|---|---|---|---|
| SEP 16 | 14.8°C | 17.0°C | |
| SEP 17 | 14.9°C | 17.0°C | |
| SEP 18 | 14.8°C | 17.0°C | |
| SEP 19 | 14.5°C | 17.0°C | |
| SEP 20 | 14.5°C | 17.0°C | |
| SEP 21 | 14.6°C | 17.0°C | |
| SEP 22 | 14.2°C | 17.0°C | |
| SEP 23 | 13.6°C | 17.0°C | |
| SEP 24 | 17.0°C | 13.8°C | |
| SEP 25 | 17.0°C | 13.9°C | |
| SEP 26 | 17.0°C | 14.1°C | |
| SEP 27 | 17.0°C | 14.3°C | |
| SEP 28 | 17.0°C | 14.5°C | |
| SEP 29 | 17.0°C | 14.6°C | |
| SEP 30 | 17.0°C | 14.8°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 | 13°C | 20°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
September 23
September 24
September 25
September 26
September 27
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.