Bilbao's climate is characterized by mild winters, with temperatures rarely dropping below freezing and often rising above 20°C. Spring brings a gradual warming trend, with March and April averaging around 11-12°C, while May sees significant temperature increases to an average of 14°C. Summer months are warm to hot, with July and August experiencing high temperatures, but also some cooler mornings. Autumn is mild, with October temperatures similar to those in late spring, before dropping again in November and December. Overall, the temperature fluctuations are relatively moderate throughout the year, with no extreme cold or heat periods.