Viana do Castelo weather in May
Temperature, sea and sunshine in May: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in May
Poor
Best time to visit: July – August
What is the weather like in Viana do Castelo in May?
In May, Viana do Castelo is mild: daytime highs average 18 °C, and nights cool down to about 13 °C. The sea averages 15.5 °C – swimming is only for the hardy. The sun shines for around 8 hours a day. Rain is frequent, with about 10 rainy days and 94 mm in total. All in all, May is not an ideal month for a holiday in Viana do Castelo.
May compared
How the weather changes from April to June. Tap a month to open it.
More details for May
- Daylight
- 14 h 30 min06:16 – 20:46
- UV index
- 9 · very highclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 21 km/haverage daily peakAll months
- Cloud cover
- 51 %on averageAll months
- Hot days
- 0 days30 °C or more
- Time zone
- UTC+1Europe/Lisbon
How the score comes together
- Temperatureweight 35 %0 %
- Seaweight 25 %0 %
- Sunshineweight 20 %90 %
- Few rainy daysweight 20 %56 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in May
- Sunscreen
- Sunglasses & sun hat
- A jumper for the evenings
- Rain jacket or umbrella
Viana do Castelo in May: quick answers
Is Viana do Castelo hot in May?
No. In May, Viana do Castelo is mild: daytime highs average 18 °C and nights drop to about 13 °C.
Can you swim in Viana do Castelo in May?
Only if you don't mind cold water: in May the sea averages just 15.5 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Viana do Castelo in May?
Rain is frequent, with about 10 rainy days and 94 mm in total.
Viana do Castelo month by month
The whole year in Viana do CasteloAll destinations: PortugalWhere to go in MaySea temperature in May
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences