Month by month
| Month | Afternoon | Sea | Rain | Verdict |
|---|---|---|---|---|
| January | 13.2 °C | 14 °C | 13 days | Possible, with trade-offs |
| February | 14.2 °C | 13.6 °C | 12 days | Possible, with trade-offs |
| March | 15.2 °C | 13.6 °C | 14 days | Possible, with trade-offs |
| April | 17 °C | 14.7 °C | 13 days | Possible, with trade-offs |
| May | 19.4 °C | 15.8 °C | 10 days | Pleasant — a good time to go |
| June | 21.1 °C | 16.8 °C | 8 days | Pleasant — a good time to go |
| July | 23.4 °C | 17 °C | 4 days | Pleasant — a good time to go |
| August | 23.4 °C | 16.9 °C | 4 days | Pleasant — a good time to go |
| September | 22.2 °C | 17 °C | 7 days | Pleasant — a good time to go |
| October | 19.7 °C | 17 °C | 14 days | Pleasant — a good time to go |
| November | 16.3 °C | 16 °C | 15 days | Possible, with trade-offs |
| December | 14.6 °C | 14.9 °C | 16 days | Possible, with trade-offs |
Before you go
Three things to check once you have picked your dates.
Entry
Portugal is in the European Union. Entry rules depend on your nationality — check before booking.
Safety
No specific restrictions
Usual precautions apply.
Official advice updated 11 August 2026
Health
Recommended vaccinations, water quality, mosquitoes: advice depends on the country and the season. Some vaccines need time before departure.
Beau Fixe is not a safety or health authority. These notes summarise public advisories and link to their source; only the competent authorities are authoritative. Alert levels: Foreign, Commonwealth & Development Office (gov.uk), Open Government Licence v3.0.
FAQ
Can you swim in Viana do Castelo in September?
The sea averages 17°C in September — too cold for most swimmers.
How hot is Viana do Castelo in September?
Expect 22.2°C in the afternoon and 15.7°C at night, averaged over the last 10 years.
Does it rain a lot in Viana do Castelo in September?
Around 7 days with rain (≥ 1 mm) in the month — 23% of days.