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 13.3°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 | 14.5°C | 16.0°C | |
| SEP 17 | 14.3°C | 16.0°C | |
| SEP 18 | 14.3°C | 16.0°C | |
| SEP 19 | 14.5°C | 16.0°C | |
| SEP 20 | 13.5°C | 16.0°C | |
| SEP 21 | 13.5°C | 16.0°C | |
| SEP 22 | 12.5°C | 16.0°C | |
| SEP 23 | 13.3°C | 16.0°C | |
| SEP 24 | 16.0°C | 13.4°C | |
| SEP 25 | 16.0°C | 13.6°C | |
| SEP 26 | 16.0°C | 13.7°C | |
| SEP 27 | 16.0°C | 13.8°C | |
| SEP 28 | 16.0°C | 14.0°C | |
| SEP 29 | 16.0°C | 14.1°C | |
| SEP 30 | 16.0°C | 14.2°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
September 23
September 24
September 25
September 26
September 27
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.