Monthly climate guide
Viana do Castelo weather in May
Expect mild weather in Viana do Castelo in May: afternoons reach about 20°C (68°F), while nights drop to around 12°C (54°F). Around 70 mm of rain falls over the month (some rain), and skies are a mix of sun and cloud. Daytime highs are 3°C warmer than April and 2°C cooler than June.
What stands out in May
- Viana do Castelo is usually about 3°C cooler than Coimbra, 170 km away, in May.
- Seasonally, May counts as late spring in Viana do Castelo.
Avg high
20°C
68°F
Avg low
12°C
54°F
Rainfall
70 mm
some rain
Humidity
78%
relative
Sky
43%
cloud · a mix of sun and cloud
Viana do Castelo weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | 13°C / 55°F | 7°C / 45°F | 141 mm | 87% | 54% |
| February | 14°C / 56°F | 7°C / 45°F | 102 mm | 84% | 51% |
| March | 15°C / 60°F | 8°C / 47°F | 111 mm | 81% | 49% |
| April | 17°C / 63°F | 10°C / 50°F | 104 mm | 81% | 52% |
| May | 20°C / 68°F | 12°C / 54°F | 70 mm | 78% | 43% |
| June | 22°C / 72°F | 14°C / 57°F | 34 mm | 74% | 41% |
| July | 26°C / 78°F | 16°C / 60°F | 13 mm | 69% | 28% |
| August | 26°C / 78°F | 16°C / 61°F | 25 mm | 69% | 30% |
| September | 25°C / 77°F | 16°C / 60°F | 52 mm | 69% | 34% |
| October | 21°C / 70°F | 14°C / 56°F | 120 mm | 76% | 46% |
| November | 16°C / 61°F | 10°C / 50°F | 152 mm | 84% | 53% |
| December | 14°C / 57°F | 8°C / 47°F | 132 mm | 86% | 54% |
What to pack for May
- T-shirts plus a light layer for the evening
- Comfortable trainers or sandals for long walks
- A compact umbrella or packable rain jacket
- Water-resistant shoes
Is May a good time to visit Viana do Castelo?
Compare the months in the chart above to find your ideal window.
Best time to visit Viana do Castelo →Other Portugal cities in May
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Viana do Castelo weather in May. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/portugal/viana-do-castelo/may
<a href="https://weathercompare.eu/weather/portugal/viana-do-castelo/may">Viana do Castelo weather in May</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/portugal/viana-do-castelo" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="Viana do Castelo weather in May"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/portugal/viana-do-castelo/may">Viana do Castelo weather in May</a> – WeatherCompare</p>
Viana do Castelo in May: quick answers
Is May a good time to visit Viana do Castelo?
May is a reasonable time for Viana do Castelo: highs around 20°C and about 70 mm of rain, though not one of the three best months.
How warm is Viana do Castelo in May?
Average highs are about 20°C (68°F) and average lows about 12°C (54°F), based on 10 years of daily data.
Does it rain a lot in Viana do Castelo in May?
Viana do Castelo typically gets around 70 mm of rain in May — some rain.
Figures are long-term averages for the area around Viana do Castelo (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.