Bilbao Weather

Its proximity to the Bay of Biscay gives Bilbao an oceanic climate (Cfb), with precipitation occurring throughout the year and without a well-defined dry summer. Precipitation is abundant, and given the latitude and atmospheric dynamics, rainy days represent 45% and cloudy days 40% of the annual total. The rainiest season is between October and April, November being the wettest. Snow is not frequent in Bilbao, although it is possible to see snow on the top of the surrounding mountains. Sleet is more frequent, about 10 days per year, mainly in the winter months. Bilbao is nearest of the subtropical boundary of all the Atlantic coastal cities in the country with an August daily mean of 20.9 °C (69.6 °F). There is also a drying trend in summer with only around 50 millimetres (2.0 in) of rainfall in July - but not dry enough to be considered Mediterranean.

The proximity of the ocean also means that the two best defined seasons (summer and winter) remain mild, with low intensity thermal oscillations. Average maximum temperatures varies between 25 and 26 °C (77.0 and 78.8 °F) in the summer months, while the average minimum in winter is between 6 and 7 °C (42.8 and 44.6 °F).

Extreme record observations in Bilbao are 42.2 °C (108.0 °F) maximum (on 13 August 2003) and −8.6 °C (16.5 °F) minimum (on 3 February 1963). The maximum precipitation in a day was 225.6 mm (9 in) in 26 August 1983 when severe flooding was caused by the Nervión river.

source: wikipedia