Climate in Bilbao
Bilbao has a humid oceanic climate typical of the Cantabrian coast. Temperatures are mild year-round, with summer highs averaging 25 degrees Celsius and winter lows rarely below 4 degrees. Annual thermal amplitude is among the smallest in the peninsula.
Rainfall exceeds 1,150 mm a year over more than 130 rainy days, which explains the permanent green of the hills around the estuary. Atlantic fronts arrive especially in autumn and winter, producing the persistent drizzle known as sirimiri.
A warm, dry southerly wind, in contrast to the usual humidity, can push winter temperatures above 25 degrees in foehn episodes from the Pyrenees, before giving way to rainy fronts.
Best time to visit is June to September, although always with an umbrella nearby. Cantabrian storms can hit the outer port and the Sopela or Plentzia coast. Use the hourly forecast, rain probability and Nervion river level before planning the Guggenheim or the Old Town.