Belfast — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Belfast, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Belfast today is 14.1°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 | 15.0°C | 16.0°C | |
| SEP 17 | 14.9°C | 16.0°C | |
| SEP 18 | 15.1°C | 16.0°C | |
| SEP 19 | 14.2°C | 16.0°C | |
| SEP 20 | 14.1°C | 16.0°C | |
| SEP 21 | 14.1°C | 16.0°C | |
| SEP 22 | 13.5°C | 16.0°C | |
| SEP 23 | 14.1°C | 16.0°C | |
| SEP 24 | 16.0°C | 14.2°C | |
| SEP 25 | 16.0°C | 14.3°C | |
| SEP 26 | 16.0°C | 14.4°C | |
| SEP 27 | 16.0°C | 14.5°C | |
| SEP 28 | 16.0°C | 14.6°C | |
| SEP 29 | 16.0°C | 14.7°C | |
| SEP 30 | 16.0°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 | 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 |
Belfast: Weather Forecast
September 23
September 24
September 25
September 26
September 27
Location & Local Information
Belfast, the capital of Northern Ireland, lies along the River Lagan, which flows through the city before entering Belfast Lough and the Irish Sea. The river’s water temperature reflects the mild but variable maritime climate of the region. In winter, the Lagan typically ranges between 4 and 6°C (39–43°F), staying cold and often brisk due to rainfall and tidal mixing near its lower reaches. By spring, it warms gradually to about 8–10°C (46–50°F). During midsummer—especially in July and August—the water can reach 15–17°C (59–63°F) in calm stretches, while the tidal section near the harbour remains slightly cooler. As autumn approaches, the temperature drops again to around 9–11°C (48–52°F), maintaining a steady freshness throughout most of the year.
Swimming in the River Lagan is possible but not widely practiced within the city limits, as the lower river is tidal and busy with boats. However, upstream sections outside the urban area provide cleaner and calmer water, suitable for wild swimming during summer. Most locals enjoy the Lagan through walking, rowing, or paddleboarding along its towpaths and calm stretches. The river is central to Belfast’s character, with nearby attractions including the Lagan Towpath, Ormeau Park, and the waterfront area around Titanic Belfast.