Derry — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Derry, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Derry today is 17.4°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 |
|---|---|---|---|
| JUL 16 | 19.1°C | 18.0°C | |
| JUL 17 | 19.1°C | 18.0°C | |
| JUL 18 | 19.3°C | 18.0°C | |
| JUL 19 | 18.8°C | 18.0°C | |
| JUL 20 | 18.6°C | 18.0°C | |
| JUL 21 | 17.9°C | 18.0°C | |
| JUL 22 | 17.8°C | 18.0°C | |
| JUL 23 | 17.4°C | 18.0°C | |
| JUL 24 | 18.0°C | 17.4°C | |
| JUL 25 | 18.0°C | 17.5°C | |
| JUL 26 | 18.0°C | 17.5°C | |
| JUL 27 | 18.0°C | 17.5°C | |
| JUL 28 | 18.0°C | 17.6°C | |
| JUL 29 | 18.0°C | 17.6°C | |
| JUL 30 | 18.0°C | 17.6°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 | 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 | 8°C | 12°C |
| December | 0°C | 4°C | 8°C |
Derry: Weather Forecast
July 24
July 25
July 26
July 27
Location & Local Information
Derry, also known as Londonderry, stands on the banks of the River Foyle in Northern Ireland, where the river widens into a tidal estuary before flowing into Lough Foyle and the Atlantic. The water here reflects the cool maritime climate of the northwest coast, with steady seasonal variation. In winter, the Foyle typically measures between 4 and 6°C (39–43°F), staying cold and fast-moving. By spring, temperatures rise gradually to around 8–10°C (46–50°F). During midsummer, particularly in July and August, the river reaches its warmest point at about 15–17°C (59–63°F), though tidal mixing keeps it feeling cool and fresh. In early autumn, the temperature falls again to 10–12°C (50–54°F), maintaining a brisk quality year-round.
Swimming in the River Foyle at Derry is possible but not generally recommended due to strong tidal currents, cold temperatures, and busy boat traffic. Wild swimming tends to take place farther upstream in calmer, narrower stretches where the flow is gentler. For those seeking time by the water, riverside walks and cycle paths offer a safer and scenic alternative. The Foyle’s waterfront is a focal point of the city, complemented by nearby attractions such as the Peace Bridge, the historic city walls, and the green hills overlooking the river valley.