Winters in Viana do Castelo are mild and cool, with temperatures ranging from around -3°C in January to a high of 16°C, averaging around 8°C. Spring brings a gradual warming trend, with April and May temperatures averaging around 14°C. Summer is warm and sunny, with July being the hottest month, averaging around 19°C, but still mild compared to other European destinations. Autumn is cool again, with October and November temperatures dropping back down to averages of 16°C and 11°C respectively. Overall, Viana do Castelo's climate is characterized by mild winters and warm summers, with spring and autumn being the cooler seasons.