Viana do Castelo Weather in May
May in Viana do Castelo averages 19°C (66°F) during the day and 13°C (55°F) at night. Quite a bit of rainfall is typical this month, with around 123 mm (4.8 in) on average. An umbrella is a good idea.
Rainfall in Viana do Castelo in May
You can expect rain on roughly 14 days based on historical data, averaging 123 mm (4.8 in) for the month. The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.
Temperature in Viana do Castelo in May
Expect highs of 19°C (66°F) in Viana do Castelo in May, with nights dropping to around 13°C (55°F). This creates a mild day-to-night pattern that is generally easy to manage with the right clothing. With lows of 13°C (55°F), nights are cool. If you're out after dark, an extra layer will keep you comfortable. The cooler air at night is also great for getting a good rest.
Sunshine in Viana do Castelo in May
With approximately 255 hours of sunshine, the days are filled with clear skies. It makes it a perfect month for being outside.If you prefer enjoying temperate temperatures and rain-free days, June, July, August and September typically offer the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Portugal, check out our Viana do Castelo's climate page.
Viana do Castelo Temperature in May
Min Temperature
13°C (55°F)
Max Temperature
19°C (66°F)
Chance of Rain
48%
Precipitation
123 mm (4.8 in)
Rainy days
14 days
Humidity
74% *
Sunshine
255 hours *
Percentage Sunshine
61% *
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Viana do Castelo typically stay consistent throughout May, with daily highs averaging around 19°C (66°F). Nights are cool, with lows typically ranging from 9°C (48°F) to 13°C (55°F).
Average temperatures in May
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in May
Historical weather for Viana do Castelo in May
Browse day-by-day weather records for Viana do Castelo spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Viana do Castelo historical weather extremes in May
Our historical data for Viana do Castelo spans 1976 to 2025, revealing these weather extremes.
- The hottest May day on record in Viana do Castelo reached 35°C (95°F) (May 28, 2001).
- The lowest daytime temperature in May was 12°C (54°F), recorded on May 8, 1981.
- Nighttime temperatures dropped to 2°C (36°F) on May 6, 1982, marking the coldest May night on record.
- The wettest May day on record brought 51 mm (2 in) of precipitation to Viana do Castelo (May 1, 2015).
Best Places in Portugal in May
Find out more about the weather in Portugal and which places have the best travel conditions in this month. See all of Portugal in May →
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What to Wear in Viana do Castelo in May
Comfortable temperatures call for an easy wardrobe in May. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. Expect heavy rainfall, so bring good rain protection and waterproof bags. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.What To Do in Viana do Castelo in May
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Portugal, check out our Viana do Castelo's climate page.
Temperature Rainfall Sunshine Humidity
See the full Viana do Castelo climate overview or explore weather in Portugal.
