Weather in Bilbao in May

A good month. May is a solid month to be in Bilbao. Highs average 17.8 °C, lows 13.6 °C, and rain falls on 12 days — nothing in the month is working against you.

May ranks 6 of 12 in Bilbao: past the worst of the year but short of July, which is the month to book if the dates are open.

Rain on 12 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 17.8 °C days and 13.6 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: the day barely swings — 4.2 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest May day reached 28.7 °C and the coldest night fell to 8.4 °C, and the wettest single day dropped 31 mm — roughly 48% of the month's rain in one day.

May is moderately variable: 27 mm in the driest year against 129 mm in the wettest, around an average of 65 mm. Roughly two Mays in three land near that average, and the third does something else entirely.

Wind is light at 13.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 79%, high enough to notice on the warm days without dominating them.

How May sits in the year

The month is on the way up: 2.3 °C warmer than April, and June adds another 3.3 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in May

14.6 hours of daylight, gaining 1.1 hours across the month. That is between Bilbao's extremes of 15.4 and 9 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 15.3 °C in May — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. The sea peaks at 21.9 °C in August and bottoms out at 12.5 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Bilbao versus nearby

If Bilbao is one option among several, the nearby comparison is worth making. Gasteiz / Vitoria is close enough to be a coin toss — within a degree on temperature, 1 day more rain. Gijón is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: May works, with July the better month by 15 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Bilbao

See all twelve months in Bilbao, or where else to go in May.