River Lagan — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in the River Lagan, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in the River Lagan today is 18.6°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 |
|---|---|---|---|
| JUL 16 | 20.1°C | 18.0°C | |
| JUL 17 | 20.2°C | 18.0°C | |
| JUL 18 | 20.2°C | 18.0°C | |
| JUL 19 | 20.1°C | 18.0°C | |
| JUL 20 | 19.5°C | 18.0°C | |
| JUL 21 | 18.9°C | 18.0°C | |
| JUL 22 | 18.9°C | 18.0°C | |
| JUL 23 | 18.6°C | 18.0°C | |
| JUL 24 | 18.0°C | 18.6°C | |
| JUL 25 | 18.0°C | 18.5°C | |
| JUL 26 | 18.0°C | 18.5°C | |
| JUL 27 | 18.0°C | 18.5°C | |
| JUL 28 | 18.0°C | 18.5°C | |
| JUL 29 | 18.0°C | 18.4°C | |
| JUL 30 | 18.0°C | 18.4°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 | 7°C |
| March | 2°C | 6°C | 9°C |
| April | 5°C | 8°C | 12°C |
| May | 9°C | 13°C | 18°C |
| June | 13°C | 18°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 | 10°C |
| December | 0°C | 4°C | 8°C |
River Lagan: Water Temperature by Location
River Lagan: Weather Forecast
July 24
July 25
July 26
July 27
Location & Local Information
Source Slieve Croob
• location Northern Ireland
• coordinates 54.340°N 5.973°W
• elevation 119 m (390 ft)
Mouth Belfast Lough
• coordinates 54.691°N 5.785°W
Length 86 km (53 mi)
The River Lagan, which flows through Belfast, maintains a generally chilly temperature throughout the year. Its urban and maritime location means the water temperature often reflects that of the surrounding sea and air, generally ranging from lows of about 7∘C to 9∘C (45∘F to 48∘F) in winter to a peak of 14∘C to 16∘C (57∘F to 61∘F) during late summer. Even at its warmest, the water requires caution and is only really suitable for activities that minimise direct contact.
Swimming is not recommended and is largely prohibited in the River Lagan, particularly in the city sections. This is primarily due to historical water quality issues, which, despite recent environmental improvements, still present a risk of infection from contaminants and urban run-off. Additionally, the river has a lot of hidden debris and heavy boat traffic, making immersion dangerous. The scenic Lagan Towpath offers miles of walking and cycling along the riverbank, connecting to attractions like the Lagan Valley Regional Park and the Neolithic earthwork, the Giant's Ring.