Viana do Castelo — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Viana do Castelo, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Viana do Castelo today is 18.9°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 |
|---|---|---|---|
| JUN 23 | 18.6°C | 19.0°C | |
| JUN 24 | 19.1°C | 19.0°C | |
| JUN 25 | 19.1°C | 19.0°C | |
| JUN 26 | 19.1°C | 19.0°C | |
| JUN 27 | 19.1°C | 19.0°C | |
| JUN 28 | 18.6°C | 19.0°C | |
| JUN 29 | 18.6°C | 19.0°C | |
| JUN 30 | 18.6°C | 19.0°C | |
| JUL 1 | 21.0°C | 19.0°C | |
| JUL 2 | 21.0°C | 19.1°C | |
| JUL 3 | 21.0°C | 19.2°C | |
| JUL 4 | 21.0°C | 19.3°C | |
| JUL 5 | 21.0°C | 19.4°C | |
| JUL 6 | 21.0°C | 19.5°C | |
| JUL 7 | 21.0°C | 19.6°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 | 5°C | 9°C | 11°C |
| February | 5°C | 8°C | 12°C |
| March | 8°C | 11°C | 14°C |
| April | 10°C | 14°C | 17°C |
| May | 13°C | 18°C | 22°C |
| June | 15°C | 19°C | 24°C |
| July | 17°C | 21°C | 26°C |
| August | 18°C | 22°C | 27°C |
| September | 15°C | 19°C | 24°C |
| October | 12°C | 16°C | 18°C |
| November | 9°C | 13°C | 16°C |
| December | 5°C | 9°C | 13°C |
Viana do Castelo: Weather Forecast
July 1
July 2
July 3
July 4
Location & Local Information
Viana do Castelo (Portuguese: Viana do Castelo), in the district of the same name on Portugal’s northwest coast, has a mix of coastal estuaries, riverine stretches and small inland lakes whose temperatures follow the Atlantic-influenced temperate climate. Freshwater bodies in the area typically register winter surface temperatures around 8–12 °C (46–54 °F), rise through spring to roughly 10–16 °C (50–61 °F), reach their warmest in summer at about 18–24 °C (64–75 °F), and cool in autumn to near 12–18 °C (54–64 °F). Actual values vary with depth, shading, inflows from rivers, and recent weather; shallow lagoons and sheltered coves warm faster than deep or fast-flowing sections.
Swimming is generally possible in lake and lagoon areas of the Viana do Castelo district but normally only in designated bathing spots where local authorities monitor water quality and safety. Permitted swimming depends on municipal rules, seasonal bathing water classifications and the absence of harmful algal blooms or bacterial contamination; lifeguards, signage and facilities may be present in popular sites during summer. Visitors should check current local advisories because cooler temperatures outside mid-summer, currents near river mouths, and occasional contamination events can make swimming inadvisable even when access is allowed.