River Tamar — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in the River Tamar, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in the River Tamar today is 18.9°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 |
|---|---|---|---|
| AUG 6 | 18.0°C | 18.0°C | |
| AUG 7 | 18.0°C | 18.0°C | |
| AUG 8 | 18.0°C | 18.0°C | |
| AUG 9 | 18.0°C | 18.0°C | |
| AUG 10 | 18.3°C | 18.0°C | |
| AUG 11 | 18.3°C | 18.0°C | |
| AUG 12 | 18.3°C | 18.0°C | |
| AUG 13 | 18.3°C | 18.0°C | |
| AUG 14 | 18.0°C | 18.9°C | |
| AUG 15 | 18.0°C | 18.8°C | |
| AUG 16 | 18.0°C | 18.8°C | |
| AUG 17 | 18.0°C | 18.7°C | |
| AUG 18 | 18.0°C | 18.7°C | |
| AUG 19 | 18.0°C | 18.6°C | |
| AUG 20 | 18.0°C | 18.6°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 | 3°C | 7°C | 9°C |
| February | 3°C | 7°C | 9°C |
| March | 4°C | 8°C | 10°C |
| April | 6°C | 9°C | 12°C |
| May | 6°C | 10°C | 15°C |
| June | 12°C | 17°C | 21°C |
| July | 13°C | 18°C | 22°C |
| August | 14°C | 18°C | 23°C |
| September | 10°C | 15°C | 19°C |
| October | 6°C | 9°C | 12°C |
| November | 4°C | 7°C | 10°C |
| December | 3°C | 7°C | 9°C |
River Tamar: Water Temperature by Location
River Tamar: Weather Forecast
August 14
August 15
August 16
August 17
August 18
August 19
Location & Local Information
Source Woolley Moor, Morwenstow parish
• location 50.9235°N 4.4622°W, Cornwall
• elevation 206 m (676 ft)
Mouth Hamoaze
• location Plymouth Sound, English Channel
• coordinates 50°21′30″N 4°10′0″W
Length 98 km (61 mi)
The River Tamar, which forms much of the border between Devon and Cornwall, exhibits a wide temperature range, particularly in its lower, estuarine sections where it is heavily influenced by the sea. In the cold winter months, the water temperature generally sits between 8∘C and 10∘C (46∘F to 50∘F). By mid-summer, the waters warm up significantly, often reaching 15∘C to 17∘C (59∘F to 63∘F), which is similar to the sea temperature in nearby Plymouth Sound.
While there is no blanket prohibition on swimming, the general advice is to exercise extreme caution. The Tamar Estuary is known for having strong tidal currents and unpredictable movements of water, which makes unsupervised swimming dangerous, particularly near the mouth and large structures like the Royal Albert Bridge. Furthermore, water quality can be variable, as with many estuaries. Despite these hazards, wild swimming is a popular local activity, and organised events like the annual Saltash Regatta Tamar Swim take place under strict safety supervision. Visitors looking for a drier experience can explore the Tamar Valley National Landscape's historic mining heritage at Morwellham Quay or visit the National Trust's beautiful medieval house, Cotehele.