River Foyle — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in the River Foyle, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in the River Foyle today is 17.1°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 60°F (15°C) to 65°F (18°C). The water is comfortable for most people, making it an ideal range for water sports enthusiasts. The temperature does not cause significant discomfort, and swimming will be pleasant for the majority. However, it's important to remember that prolonged exposure to the water can still lead to cooling, so it's essential to monitor the time spent in the water, especially for children or elderly people. 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 | 17.1°C | 18.0°C | |
| AUG 7 | 16.8°C | 18.0°C | |
| AUG 8 | 16.5°C | 18.0°C | |
| AUG 9 | 16.6°C | 18.0°C | |
| AUG 10 | 16.8°C | 18.0°C | |
| AUG 11 | 16.7°C | 18.0°C | |
| AUG 12 | 16.6°C | 18.0°C | |
| AUG 13 | 16.6°C | 18.0°C | |
| AUG 14 | 18.0°C | 17.1°C | |
| AUG 15 | 18.0°C | 17.2°C | |
| AUG 16 | 18.0°C | 17.2°C | |
| AUG 17 | 18.0°C | 17.3°C | |
| AUG 18 | 18.0°C | 17.3°C | |
| AUG 19 | 18.0°C | 17.4°C | |
| AUG 20 | 18.0°C | 17.4°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 | 4°C | 7°C |
| February | 0°C | 4°C | 8°C |
| March | 2°C | 6°C | 9°C |
| April | 5°C | 8°C | 12°C |
| May | 9°C | 13°C | 18°C |
| June | 12°C | 17°C | 22°C |
| July | 14°C | 18°C | 23°C |
| August | 14°C | 18°C | 23°C |
| September | 11°C | 16°C | 20°C |
| October | 8°C | 11°C | 14°C |
| November | 4°C | 7°C | 11°C |
| December | 0°C | 4°C | 8°C |
River Foyle: Water Temperature by Location
River Foyle: Weather Forecast
August 14
August 15
August 16
August 17
August 18
August 19
Location & Local Information
Source River Finn and River Mourne
• location Newtownstewart
• coordinates 54.721°N 7.365°W
Mouth Lough Foyle
• coordinates 55.107°N 7.079°W
Length 32 km (20 mi)
The River Foyle, which flows through Derry/Londonderry before emptying into Lough Foyle, is a tidal estuary for a significant length, which influences its temperature. In the colder winter months, the water temperature is consistently chilly, typically ranging between 7∘C and 10∘C (45∘F to 50∘F). During summer, the Foyle warms slightly, but still remains cool, with temperatures usually peaking between 14∘C and 17∘C (57∘F to 63∘F).
While there are occasional organised swimming events, public, unsupervised swimming in the River Foyle is strongly discouraged and is not recommended by local authorities. The river is highly dangerous due to the combination of strong, unpredictable currents and tides, particularly near the city, and the very low water temperature which presents a serious risk of cold water shock and hypothermia, even in summer. Furthermore, water quality can be a concern due to runoff. Visitors to the area are encouraged to walk along the riverbanks, perhaps crossing the iconic Peace Bridge , or explore the city's main historical attraction, the beautifully preserved Derry Walls.