Climate in Viana Do Castelo (Portugal)

The climate of Viana do Castelo is temperate oceanic, with mild, rainy winters and pleasantly warm, sunny summers.
The city is located in the extreme north-west of Portugal (the rainiest area of the country), on the coast, at the mouth of the Lima River.
The wind blows frequently: in the cold half-year, it is caused by Atlantic depressions, and can be strong, while in summer, a cool breeze from the sea blows in the afternoon.
During the night and the early morning, in periods of good weather, fog can form all year round.
The average temperature of the coldest month (January) is of 9.8 °C (49.5 °F), that of the warmest month (July) is of 20.8 °C (69.5 °F). Here are the average temperatures.

Precipitation amounts to 1,470 millimeters (57.9 inches) per year: it is therefore abundant. It ranges from 30 mm (1.2 in) in the driest months (July, August) to 230 mm (9.1 in) in the wettest (December). The rains are frequent from October to May, while from June to September it rains quite rarely (but more often than in south-central Portugal). Here is the average precipitation.

Winter, from December to February, is mild: daytime temperatures hover around 14/15 °C (57/59 °F). The rains occur in periods of bad weather, which last a few days, and may be abundant.
Compared to Lisbon, cold days are more likely, while snow is hardly ever seen. The last snowfall of some importance occurred in January 1987.
On the coldest nights of the year, the temperature typically drops to around -2/0 °C (28/32 °F). The coldest record is -4.5 °C (24 °F), recorded in December 2001.

Summer, from June to mid-September, is mild or pleasantly warm. In fact, there are quite cool periods, with highs around 20/23 °C (68/73 °F), and sometimes even lower in June, and warmer periods, with temperatures hovering between 26 °C and 30 °C (79 and 86 °F).
Sometimes, from mid-June to early September, heat waves can occur, usually of short duration, in which the temperature can reach 36/37 °C (97/99 °F). However, this happens less often than in south-central Portugal.
The highest record is 39.5 °C (103 °F), recorded in August 2003.
In summer, the weather is usually good, but some Atlantic fronts bringing clouds and rain can not be excluded, especially in June, which, to tell the truth, often resembles a spring month.



On average, there are around 2,350 sunshine hours per year: therefore, the amount of sunshine is good. Here are the average sunshine hours per day.

The sea temperature ranges between 14 °C (57 °F) and 19 °C (66 °F). So, it never becomes warm for swimming. Here are the average sea temperatures.

Best Time

The best time to visit Viana do Castelo runs from June to September, since it is the warmest and the least rainy period of the year. July and August are the warmest months, but the heat is rarely excessive, and in addition, they are the driest. However, in September too, the rains are still quite rare, at least in the first half. In May, you can go, but cool and rainy days are more frequent.
Even in summer, it's better to bring a sweatshirt, and maybe a light jacket for the evening.
Those who want to avoid hot periods (which are quite rare, but possible) can choose the period from early May to mid-June and from mid-September to early October, although it rains more often.